This paper presents a method for quantitative assessment of the mechanisms of nucleation and granules growth by layering in the process of bed wetting during periodic disc granulation. This study included two initial, consecutive stages of a process with defined time courses. The first phase was a time period, in which only formation of new nuclei took place, while in the second stage simultaneous nucleation and growth of granules as a result of sticking raw material grains to pre-existing nuclei occurred. Different kinds of binding liquid were used for bed wetting in each phase. In the first phase, an aqueous solution of dye was used, and pure distilled water in the second stage. The contribution of particular mechanisms to the formation of agglomerates at different time points within the second phase of the process was determined in this study. To do that the results of bed granulometric analysis, mass balance of size fractions and the analysis of contents of a marker (dye) delivered to the bed with the binding liquid during the first phase in agglomerates were used. To assess the concentration of the dye in different size fractions of the batch, spectrophotometric analysis was utilised. The study was performed using UV-VIS JASCO V-630 spectrophotometer equipped with an integrating sphere. The sieve analysis, spectrophotometric studies and mass balance were used to determine changes in the weight of the dye containing nuclei and of the nuclei containing no dye. The aforementioned analyses were also used to assess changes in the weight of formed granules and of raw material particles attached to nuclei during simultaneous nucleation and growth of granules.
The starting point of the study on the problems, dilemmas and hopes for effective implementation of revitalization projects in Polish cities was the conviction that revitalization is one of the processes affecting the development and changes in the spatial and functional fabric of cities. Revitalization is defined as a deliberate and purposeful process, the effect of which is to restore life in the dysfunctional and degraded parts of cities. Taking up such a topic required an answer to the question about the nature of revitalization and its aspects. The focus of the study was on the problems of revitalization that stem from the legal and socio-economic situation and the dilemmas faced by local government authorities of Polish cities. The introduction to these considerations is the brief outline of the revitalization of Polish cities in the period after World War II, while the conclusion deals with the fears and hopes related to revitalization activities that are presently initiated. The discussion takes into account the existing, critically assessed, legal regulations on revitalization.
One of the current challenges in transport is e-mobility, understood as electromobility, ecomobility and mobility economics. E-mobility is nowadays a key focus area of socio-technical change, in terms of attention from policy makers as well as from industry and the public. The societal challenges ahead, in particular climate change put increasing pressure on the current mobility system, due to its tremendous environmental impact. Furthermore e-mobility is seen as major economic opportunity for the automotive industry. In this context, based on the available literature and documents and practical solutions implemented already in cities and agglomerations, the paper discusses the fundamental challenges that cities are to face in the context of the current megatrends. This process will engage diff erent stakeholders in order to make this concept become a reality.
Local development, based on the use of endogenous potentials, requires the cooperation of muni-cipalities in urban functional areas (agglomerations). However, conducting joint activities in the area of building and running local development policy is a serious challenge. On the one hand, there is a shortage of experience in this area (not counting the short period of functio-ning municipal unions in the years 1920-1939 and intentional inter-communal relations after 1990). In addition, there are still no legal solutions needed (in addition to the act passed in 2017 for the metropolis of Silesia and Zagłębie). In recent years, however, projects of integra-ted territorial investments and other project partnerships have been implemented under the European Union and the Norwegian Financial Mechanism Programs, which result in prac-tical conclusions and legislative recommendations. The most important of them concern the introduction of a new form of partner cooperation and the adoption of a new urban code. Their quick implementation will enable more eff ective cooperation for development.
In the heterogeneous economic space, big cities are development poles that are usually characterized by the best conditions for running a business and the highest level and living conditions. Their role in development processes is the subject of many discussions. On 23 October 2017, at the invitation of the Mayor of Cracow, J. Majchrowski, an external Plenary meeting of the Committee for Spatial Development of the Polish National Academy of Sciences was held in Cracow, the aim of which was to discuss the role of big cities in Poland›s socio-economic development. This article presents the author›s opinions in a synthetic way, presenting the most important issues raised by him during the panel on the importance of Polish metropolises in shaping the development potential of the country and the region. In addition to the fundamental terminological and problematic discussion, the article describes the experience of Poznań as an agglomeration signifi cantly aff ecting the development of the region, formulating in the summary recommendations referring to the practice of regional policy.