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Number of results: 22
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Abstract

Clusters belong to the regional innovation system, which led to the formulation and implementation of the cluster-based policy in many countries. The positive impact of clusters on the competitiveness of regions was confirmed by empirical studies. Absence of clusters means retardation in a regional development. The implementation of cluster policy supporting coopetition into the scope of principled regional policy assumptions seems urgent. In this way effective conditions for the formation of growth poles around industries specific for a given region will be developed and, consequently, the economic specialization of individual regions will be achieved. Observation of the benefits resulting from the functioning of clusters in the region, taking into account their possible negative impact, will allow to determine the specificity of regional development policy based on clusters. These problems indicated above are the subject of this study, based on the Polish and foreign literature available on the subject employing the desk research method.
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Abstract

An analysis of the power system functioning and the behaviors of the energy market participants allows the trends taking place within years to be identified, including these associated with the evolution of the electric energy and power demand profiles. The problems of balancing the peak power demand are of both a short and long term nature, which implies the need for changes in the electricity generation sector. Apart from the existing “silo-type” generation units, the construction of distributed energy sources implemented in the civic formula in the framework of self-sufficient energy communes and energy clusters is becoming increasingly important. Support for these programs is realized both at the legislative level, as well as within dedicated competitions and ministerial activities. The financial support carried out by the National Fund for Environmental Protection and Water Management and the Regional Operational Programs is also noticeable. One of the activities aimed at spreading the idea of clustering was the competition for certified energy clusters, conducted by the Ministry of Energy. The goal of the contest was the promotion and development of the distributed energy sector, which could be used for the improvement of energy security in the local manner and constitute a basis for the knowledge necessary in planning and developing the state’s energy policy. The paper presents a synthetic analysis of the results of the competition for a certified energy cluster from the perspective of planning and operational needs related to the functioning of the power system. Further, the information about the investment plans of new generation capacities, including their breakdown with respect to type, achievable power and costs has been provided. Also, the balancing of the demand for electric energy by own generation within the energy clusters has been characterized for three time perspectives
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Abstract

The development of electromobility is a challenge for the power system in both technical and economic-market terms. As of today, there are no analyses to determine the power necessary to supply the planned infrastructure and to estimate the incentives and economic benefits resulting from the modification of the settlement method. The document determining the legal regulations and the obligation to build vehicle charging stations for specific municipalities is the Act on Electromobility and Alternative Fuels. This act estimates that the development of electromobility, due to the specifics including not only individual vehicles, will take place in certain areas. The places which in the first stage will be dedicated to the potential implementation of the concept of electromobility will be municipalities covering large agglomerations. In addition, due to the local aspect, the development of electromobility may take place in the areas of energy clusters’ initiatives, which, using the policy of increasing energy awareness, are aimed at energy production from local renewable energy resources. The planned development of electromobility assumes a systematic increase in the number of electric cars caused by the introduction of support systems. The dynamization of this sector will cause an increase in the demand for electricity. Due to power system reasons, an important factor determining the level of energy consumption depending on the time of day may be an appropriate shape of the pricing for the charging service. Appropriate price list stimulation can affect the behavior of recipients, causing the charging of cars in the off-peak of electricity demand. The aim of the article is to characterize the scale of the phenomenon of electromobility in the context of the emergence of a charging points infrastructure along with the possibility of price-setting stimulation affecting the profile of energy demand. It is also important to consider the challenges and responsibilities of municipalities and energy clusters from the perspective of introducing electromobility.
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Abstract

In spite of technological, logistic and economic difficulties, interest in renewable energy sources in the world is consistently increasing. This trend is also observed in Poland, mainly due to the urgent need to tackle the problem of climate change, which is caused by the increasing concentration of gaseous pollutants in the atmosphere. The paper presents a short script of the issue of estimating renewable energy resources in Poland in the context of creating local low carbon economy plans at the level of municipalities/counties where RES sources should be taken into account. The author proposed an individual approach to estimate the potential of RES, taking the local conditions and the short characteristics of the small and medium companies sector in Poland into account. These companies have a great application potential to increase the share of renewable energies and to improve energy efficiency in their business. The actions, which are taken by the Ministry of Energy in the field of civil energy development, enhancing local energy security and the sustainable development of renewable energy resources support the development of energy clusters covering one district or five municipalities. In the article, the author presents data on the number of companies possessing a concession for generating electricity in RES installations in the power range from 40 kW to 200 kW. These companies can largely be the nucleus for creating a local cluster in which microgrids will be a key element.
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Abstract

Economic development is strictly dependent on access to inexpensive and reliable energy sources based on diversified primary fuels. The strategic framework for the construction of the energy mix is defined in the Energy Policy of the State, the content of which, in terms of its mandatory elements, has been specified in the Energy Law. The task of the Energy Policy of the State is to create the shape of the future power sector, including designing the most advantageous regulatory, system and technical solutions guaranteeing the appropriate level of energy security of the country, monitoring of the system’s evolution and also designing and implementing changes aimed at the optimization of the functioning mechanisms. The vision of the development of the power system at the global level should also reflect changes in the formation of dispersed civil energy structures. Unfortunately, the results of the conducted analyses reveal existing imperfections of the data acquisition and information system, which should be used in the planning process. This issue is particularly important from the perspective of the dynamically developing concept of the energy self-sufficiency of communes and the emergence of energy clusters. The present paper describes the functioning of strategic planning in the field of the electric power system with an illustration of the improperly functioning mechanisms of information transfer in the context of the advancement of dispersed civil energy structures.
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Abstract

Pollution, climate change and energy security are significant problems. Climate-disrupting fossil fuels are being replaced by clean and non-depletable sources of energy. It requires major changes to energy infrastructures and strong support for promotion of the use of energy from renewable sources. Renewable energy is emerging as a driver of inclusive economic growth and reinforcing energy security. Public entities have to promote renewable energy development by implementing cost-effective national support schemes. By acting at national-level, several barriers to public and private investments could be tackled, addressing the lack of coordination between various authorising bodies at national level and stimulatng the administrative capacity to implement energy projects. It should be effective in promoting transparency for investors and others economic operators. In Poland there is a lack of regulatory policies creating incentives for decentralised energy. Market-based support schemes are still needed for small-scale self-consumption system. Currently operating solutions have been shown in the contrast of the ones applied abroad. The development of clean energy technologies depends on many factors. The author identified few most important ones, mainly financial, regulatory issues, social, environmental and characterized them in this work. The article presents the recommendations of regulatory framework and some proposals for energy cluster based policy’s tools, the introduction of which would significantly facilitate the wider renewable energy uses in Poland.
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Abstract

The article deals with the patterns of segmental adaptation of Polish voiceless affricates in initial and fi nal CC (consonant + consonant) clusters by native speakers of English. The data have been collected in an online loanword adaptation experiment in which 30 native speakers of Southern British English reproduced Polish words containing such sequences. The major problem posed by the data is the divergent adaptation of the post-alveolar /͡tʂ/ vs. the pre-palatal /͡tɕ/, with the former substituted mainly with the coronal plosive [t] and the latter realised as the palato-alveolar affricate [͡tʃ]. It is argued that these patterns of nativisation are due to the highlyranked IDENT-IO[dist] constraint, which militates against the modifi cation in the value of the feature [distributed]. Furthermore, it is demonstrated that the experimental results provide evidence in favour of the fundamental assumptions underlying the phonological approach to loan assimilation, namely the phonological input view as well as the faithful perception view.
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Abstract

The article deals with the issue of formation and functioning of rural tourism clusters in Ukraine. Here, formation of cluster structures in rural tourism is at its initial stage. Analysis of existing clusters resulted in their classification into groups based on the criterion of specialization: lodging and food (farmsteads), agritourist and local history tourism clusters. Analysis of the main research models for the creation and analysis of rural tourism clusters functioning has been performed. A multilevel universal model of the rural tourism clusters with basic structural levels (basic, affiliate and accompanying) has been proposed for scientific and practical purposes. This model was used to form two cluster initiatives in the ethnographic region of the Ukrainian Carpathians – in the Boykivshchyna. The need to use foreign experience in rural tourism cluster research has been emphasized.
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Abstract

The Energy Law of April 10, 1997 initiated changes in the energy market in Poland. Actions taken on the basis of this law were aimed at the modernization and development of the power sector. Organizational and legal changes causing the development of distributed generation, thus increasing the level of market competition have been introduced. The care for high quality of customer service, including the protection of vulnerable customers, environmental protection, growing share of renewable energy and emission reduction requirements have become a reality. It seems, therefore, that it is necessary for the Polish energy sector to undergo permanent modernization, to develop the production and industrial infrastructure and to develop modern conventional technologies by way of implementing innovations in the field of energy companies. The author of the paper argues that it is indispensable to make a broadly understood transfer of knowledge and technology to the energy sector on the basis of a knowledge-based economy. This also applies to energy clusters, which currently constitute a platform for cooperation: entrepreneurs, scientific-research units, and public authorities. The functioning of these entities is an important catalyst for the transfer of knowledge and technologies. Their regional nature boosts competitiveness of the involved enterprises, and is a natural way of transferring knowledge to the energy market.
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Abstract

The article concerns safety of power supply for the final consumers, especially its two comprising elements, which are generation adequacy and distribution system reliability. Generation adequacy has been defined with Loss of Load Probability (LOLP), Loss of Load Expectation (LOLE) and Energy Not Supplied (ENS) indices. Conclusions from generation adequacy forecast prepared by ENSTO-E for Poland compared with other European countries for the years 2020 and 2025 have been discussed along with the resulting threats. Interruptions in energy supply have been characterised by power discontinuity indicator SAIDI. Finally, a reliability and adequacy analysis have been performed for different scenarios of the Polish power system operation in order to assess possibilities of using distributed generation as a backup power source. Based on a simulation model created using the DIgSILENT Power Factory software, the reliability and adequacy calculations have been performed with the probabilistic non-sequential Monte Carlo method and they are followed by a discussion of the obtained results.
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Abstract

The purpose of this work is to find a correlation for heat transfer to walls in a 1296 t/h supercritical circulating fluidised bed (CFB) boiler. The effect of bed-to-wall heat transfer coefficient in a long active heat transfer surface was discussed, excluding the radiation component. Experiments for four different unit loads (i.e. 100% MCR, 80% MCR, 60% MCR and 40% MCR) were conducted at a constant excess air ratio and high level of bed pressure (ca. 6 kPa) in each test run. The empirical correlation of the heat transfer coefficient in a large-scale CFB boiler was mainly determined by two key operating parameters, suspension density and bed temperature. Furthermore, data processing was used in order to develop empirical correlation ranges between 3.05 to 5.35 m·s-1 for gas superficial velocity, 0.25 to 0.51 for the ratio of the secondary to the primary air, 1028 to 1137K for bed temperature inside the furnace chamber of a commercial CFB boiler, and 1.20 to 553 kg·m-3 for suspension density. The suspension density was specified on the base of pressure measurements inside the boiler’s combustion chamber using pressure sensors. Pressure measurements were collected at the measuring ports situated on the front wall of the combustion chamber. The obtained correlation of the heat transfer coefficient is in agreement with the data obtained from typical industrial CFB boilers.
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Abstract

The interrelation between fuzzy logic and cluster renewal approaches for heat transfer modeling in a circulating fluidized bed (CFB) has been established based on a local furnace data. The furnace data have been measured in a 1296 t/h CFB boiler with low level of flue gas recirculation. In the present study, the bed temperature and suspension density were treated as experimental variables along the furnace height. The measured bed temperature and suspension density were varied in the range of 1131–1156 K and 1.93–6.32 kg/m3, respectively. Using the heat transfer coefficient for commercial CFB combustor, two empirical heat transfer correlation were developed in terms of important operating parameters including bed temperature and also suspension density. The fuzzy logic results were found to be in good agreement with the corresponding experimental heat transfer data obtained based on cluster renewal approach. The predicted bed-to-wall heat transfer coefficient covered a range of 109–241 W/(m2K) and 111–240 W/(m2), for fuzzy logic and cluster renewal approach respectively. The divergence in calculated heat flux recovery along the furnace height between fuzzy logic and cluster renewal approach did not exceeded ±2%.
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Abstract

This paper focuses on assessment of the effect of flue gas recirculation (FGR) on heat transfer behavior in 1296t/h supercritical coal-fired circulating fluidized bed (CFB) combustor. The performance test in supercritical CFB combustor with capacity 966 MWthwas performed with the low level of flue gas recirculation rate 6.9% into furnace chamber, for 80% unit load at the bed pressure of 7.7 kPa and the ratio of secondary air to the primary air SA/PA = 0.33. Heat transfer behavior in a supercritical CFB furnace between the active heat transfer surfaces (membrane wall and superheater) and bed material has been analyzed for Geldart B particle with Sauter mean diameters of 0.219 and 0.246 mm. Bed material used in the heat transfer experiments had particle density of 2700 kg/m3. A mechanistic heat transfer model based on cluster renewal approach was used in this work. A heat transfer analysis of CFB combustion system with detailed consideration of bed-to-wall heat transfer coefficient distributions along furnace height is investigated. Heat transfer data for FGR test were compared with the data obtained for representative conditions without recycled flue gases back to the furnace through star-up burners.
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Abstract

Experimental research has been carried out in a supercritical circulating fluidized bed combustor in order to indicate the effect of the bed particle size on bed-to-wall heat transfer coefficient. The bed inventory used were 0.219, 0.246 and 0.411 mm Sauter mean particles diameter. The operating parameters of a circulating fluidized bed combustor covered a range from 3.13 to 5.11 m/s for superficial gas velocity, 23.7 to 26.2 kg/(m2s) for the circulation rate of solids, 0.33 for the secondary air fraction and 7500 to 8440 Pa pressure drop. Furthermore, the bed temperature, suspension density and the main parameters of cluster renewal approach were treated as experimental variables along the furnace height. The cluster renewal approach was used in order to predict the bed-to-wall heat transfer coefficient. A simple semi-empirical method was proposed to estimate the overall heat transfer coefficient inside the furnace as a function of particle size and suspension density. The computationally obtained results were compared with the experimental data of this work.
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Abstract

In the study suitability of water quality index approach and environmetric methods in fi ngerprinting heavy metal pollution as well as comparison of spatial variability of multiple contaminants in surface water were assessed in the case of The Gediz River Basin, Turkey. Water quality variables were categorized into two classes using factor and cluster analysis. Furthermore, soil contamination index was adapted to water pollution index and used to fi nd out the relative relationship between the reference standards and the current situation of heavy metal contamination in water. Results revealed that surface water heavy metal content was mainly governed by metal processing, textile and tannery industries in the region. On the other hand, metal processing industry discharges mainly degraded quality of water in Kemalpasa and Menemen. Furthermore, Kemalpasa region has been heavily affected from tannery and textile industries effl uents. Moreover, pollution parameters have not been infl uenced by changes in physical factors (discharge and temperature). This study indicated the effectiveness of water quality index approach and statistical tools in fi ngerprinting of pollution and comparative assessment of water quality. Both methods can assist decision makers to determine priorities in management practices.
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Abstract

The paper discusses possible applications of the percolation theory in analysis of the microstructure images of polycrystalline materials. Until now, practical use of this theory in metallographic studies has been an almost unprecedented practice. Observation of structures so intricate with the help of this tool is far from the current field of its application. Due to the complexity of the problem itself, modern computer programmes related with the image processing and analysis have been used. To enable practical implementation of the task previously established, an original software has been created. Based on cluster analysis, it is used for the determination of percolation phenomena in the examined materials. For comparative testing, two two-phase materials composed of phases of the same type (ADI matrix and duplex stainless steel) were chosen. Both materials have an austenitic - ferritic structure. The result of metallographic image analysis using a proprietary PERKOLACJA.EXE computer programme was the determination of the content of individual phases within the examined area and of the number of clusters formed by these phases. The outcome of the study is statistical information, which explains and helps in better understanding of the planar images and real spatial arrangement of the examined material structure. The results obtained are expected to assist future determination of the effect that the internal structure of two-phase materials may have on a relationship between the spatial structure and mechanical properties.
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Abstract

The aim of this article is to evaluate the quality of the Danube River in its course through Serbia as well as to demonstrate the possibilities for using three statistical methods: Principal Component Analysis (PCA), Factor Analysis (FA) and Cluster Analysis (CA) in the surface water quality management. Given that the Danube is an important trans-boundary river, thorough water quality monitoring by sampling at different distances during shorter and longer periods of time is not only ecological, but also a political issue. Monitoring was carried out at monthly intervals from January to December 2011, at 17 sampling sites. The obtained data set was treated by multivariate techniques in order, firstly, to identify the similarities and differences between sampling periods and locations, secondly, to recognize variables that affect the temporal and spatial water quality changes and thirdly, to present the anthropogenic impact on water quality parameters.
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Abstract

Eighteen sediment samples from a 36 cm long sediment core retrieved from a proglacial lake (namely P 11) situated in the Schirmacher Oasis, East Antarctica, were analysed for the study of quartz grain morphology and microtexture, along with sand percentage, to reconstruct the paleoenvironmental changes in the lake during the Holocene. The age of the core ranges from 3.3 ka BP to 13.9 ka BP. The quartz grain morphology and microtexture reveal significant evidences of glacial transport along with some eolian and aqueous activities. On the basis of predominance of these signatures and the zonation from CONISS Cluster Analysis on the percentages of characteristic grain morphology and microtextures, the entire core has been subdivided into three major zones. From the paleoenvironmental perspective, it can be concluded that there is an onset of interglacial period at the advent of Holocene (12.3 ka BP), which reigned until 5.3 ka BP and thereafter, again a glacial environment prevailed until 3.3 ka BP with some variations in-between. The results indicate probable alternative colder and less colder phases in the study area, which are also well supported by the respective sand percentages in the sediments. © 2017 Polish Academy of Sciences 2017.
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