Unique marshland area in the Danube floodplain -Special Nature Reserve Gornje Podunavlje is considered to be one of the last aquatic flora and fauna refuges in the region. The revitalization projects in SNP Gornje Podunavlje started in 2011. They were conducted in order to protect biodiversity and to provide the natural ecosystem. The aim of this study was to investigate and compare the present diversity and distribution of the charophytes in five ponds of SNR Gornje Podunavlje, depending on phases of the revitalization process within the ponds. The researched area includes the following ponds: Semenjača, Šarkanj, Široki rit, Sakajtaš and Ribolov. The Široki rit pond was under the process of revitalization during the field surveys, Semenjača and Šarkanj have already been revitalized, and Ribolov and Sakajtaš were not exposed to the revitalization processes at all. The field surveys were conducted monthly, from May to September 2016. Water quality parameters were measured in situ and in laboratory. Ponds differed considerably when it comes to water chemistry; Semenjača and Šarkanj were associated with highest nutrient concentrations, while Široki rit was characterized by highest conductivity and water hardness. The highest diversity was found in Široki rit pond, which was still in process of revitalization when the field survey was conducted. Charophytes were not detected within previously revitalized ponds (Semenjača and Šarkanj). Eight species of charophytes were detected:

No abstract

Dry micronizing grinding of mineral raw materials is a very complex process and depends on a whole range of parameters such as: shape, particle size, size distribution of the starting and micronized material, hardness, moisture, density, surface properties, structural characteristics of mills, etc. In order to obtain a clear picture of dry micronizing milling process, a good knowledge of the theoretical principles of high-energy mills operation is necessary. Classical mills are not suitable for micronization to a fine and particularly very fine particles size (upper particle size limit below 5 μm), which is necessary for modern industrial application domains. The intensive fundamental and developmental research of the dry micronizing milling process for the new materials development has also enabled the development of new construction solutions for ultra-fine high-energy mills-mechanics. These mills have found application into the state-of-the-art production technologies of new very profitable materials. For the production of powders-particles of micron dimensions, the mechano-actuators are used and all micronizers-disintegrators, colloidal (perl mills), vibratory, planetary, ultra-centrifugal mill, Jet-current mills and others operate on the principle of impact, shock and friction. This paper presents the experimentally achieved results of dry micronizing grinding of zeolites in a vibrating mill with rings, as well as the improvement of its reactivity. All experimental micronization investigations were carried out on a previously prepared coarse particle size class (-3.35 + 0) mm with different starting mass (50 g and 200 g), and carried out in different grinding time intervals (45, 120, 900 seconds), in order to examine the impact of these parameters on the micronization process. Grinding success was evaluated by the particle size measurements and content of class (-5 + 0) μm, and particle specific surface. It was shown that for a sample of four times larger initial mass it is need longer grinding time to achieve the maximum content of the class (-5 + 0) μm, but for a sample of the bulk class (-3.35 + 0) mm with a lower starting mass the effects of amorphization due to prolonged micronizing grinding are very pronounced, and the zeolite minerals in crystalline form are practically in the trace and the largest part is amorphous. Generally, it can be concluded that a vibrating mill with a rings proved to be a good device for efficient ultra-fine micronizing grinding.

No abstract

Over the years, alternative procedures to the Bond grindability test have been proposed aiming to avoid the need for the standard mill or to reduce and simplify the grinding procedure. Some of them use the standard mill, while others are based on a non-standard mill or computation techniques. Therefore, papers targeting to propose a better alternative claim to improve validity, to reduce test duration, or to propose simpler and faster alternative methods for determining the Bond work index (wi). In this review paper, a compilation and critical analysis of selected proposals is performed, concluding that some of the short procedures could be useful for control purposes, while the simulation-based procedures could be interesting within a process digitalisation strategy.