This paper summarizes the arguments and counterarguments within the scientific discussion
on developing the free-carbon economy in Ukraine. The main purpose of the paper is elaborating
the energy efficiency profile of Ukraine to assure the development of the free-carbon economy. To
achieve this purpose, the authors carried out an investigation in the following logical sequence.
Firstly, the bibliometric analysis of 4674 of the most cited articles indexed by the Scopus database
was conducted. The obtained findings indicated that the green economy transformation depended
on the main factors such as economic performance, corruption, macroeconomic stability, social
welfare, shadow economy etc. As a result, the forecast of the final energy consumption to 2030
was performed. The methodological tool of this research is based on the Autoregressive Integrated
Moving Average (ARIMA) model. This study involved data of the Visegrad countries (Poland, the
Czech Republic, the Slovak Republic and Hungary) and Ukraine from 2000 to 2018. The base of
data is Eurostat, the EU statistical service. Based on the obtained results of analyzing the green
economic transformation in the Visegrad countries and Ukraine, the authors intimated the existence
of the significant energy-efficient gap in Ukraine compared to the analyzed countries. In reliance on
the experience of the Visegrad countries and the forecast results, the authors provided the main recommendations
for providing the green transforming in Ukraine. The authors highlighted that the obtained
results of this paper were considered to be the base for future investigations considering the influence
of endogenous and exogenous factors on developing the free-carbon economy in Ukraine.
Noise reduction inside waveguide systems has gained momentum owing to a great interest in it. To attenuate the sound in a broad frequency range, this study aims to compare the effects of two acoustic liners, a perforated plate backed by an air cavity (PP-Air cavity), or by a porous material (PP-PM), on the acoustic behaviour of lined ducts using a numerical model to compute the multimodal scattering matrix. From this matrix, the reflection and the transmission coefficients are computed and therefore the acoustic power attenuation is deduced. Moreover, the effects of geometry of ducts with and without changes in the section are investigated. The numerical results are obtained for five configurations, including cases of narrowing and widening of a duct portion with sudden or progressive discontinuities. Accordingly, numerical coefficients of reflection and transmission as well as the acoustic power attenuation show the relative influence of acoustic liners in each type of configuration.
Consumption of energy is one of the important indicators in developing countries, but a lot of companies from the energy sector have to cope with three key challenges, namely how to reduce their impact on the environment, how to ensure the low cost of the energy production and how to improve the system overall performance? For Polish energy market, the number of challenges is greater. The growing demand for electricity and contemporary development of nuclear power technology allow today’s design, implement new solutions for high energy conversion system low unit cost for energy and fuel production. In the present paper, numerical analysis of modular high-temperature nuclear reactor coupled with the steam cycle for electricity production has been presented. The analysed system consists of three independent cycles. The first two are high-temperature nuclear reactor cycles which are equipped with two high-temperature nuclear reactors, heat exchangers, blowers, steam generators. The third cycle is a Rankine cycle which is equipped with up to four steam turbines, that operate in the heat recovery system. The analysis of such a system shows that is possible to achieve significantly greater efficiency than offered by traditional nuclear reactor technology.
Studies on the quality of bituminous coal are mainly focused on physico-chemical analysis, examining the ash content, sulphur content, volatile matter content, moisture content, and the Net Calorific Value of coal. Until now, the above mentioned parameters form the basis of the Polish Standard PN-82/87002, on the basis of which individual types of bituminous coal are determined. In addition, an elemental analysis, providing information about the content of primary elements in the organic matter of solids, i.e. coal, hydrogen, nitrogen, oxygen, and sulphur, is carried out for the selected samples. This issue has been studied by many authors, which undoubtedly provide invaluable knowledge due to the huge amount of data, but, as the authors themselves indicate, the knowledge of the petrography of coal, coking properties (Probierz et al. 2012) and finally the coke obtained from individual coal types (based on tests carried out using the Karbotest installation or the so-called „box tests” performed in the coke oven battery) is still very limited. The article discusses the impact of petrographic composition on the quality of metallurgical coke. The analysis was performed using samples of coking coal from the following mines: Pniówek, Zofiówka, Borynia, and Krupiński. The mentioned coal types are used to produce coke mixtures used for the production of coke in the Przyjaźń and Radlin coking plants. Based on the rank of coal and physicochemical parameters, the mentioned coal types were classified according to the Polish classification and the UN/ECE International Classification of In-Seam Coals (UN/ECE 1995). The prediction of thermomechanical properties of coke (CSR and CRI) performed according to the original CCP method were compared with the results obtained using the classical method of Nippon Steel Corporation.
The aim of this paper is to present a way of ranking the nonlinearities of electrodynamic loudspeakers. For this purpose, we have constructed a nonlinear analytic model which takes into account the variations of the small signal parameters. The determination of these variations is based on a very precise measurement of the electrical impedance of the electrodynamic loudspeaker. First, we present the experimental method to identify the variations of these parameters, then we propose to study theoretically the importance of these nonlinearities according to the input level or the input frequency. We show that the parameter which creates most of the distortions is not always the same and depends mainly on both the input level and the input frequency. Such results can be very useful for optimization of electrodynamic loudspeakers.
Background: The older population is very heterogeneous with regard to the co-morbidity and the physical reserve. This can result in unacceptably high postoperative complications rates. Th erefore, the aim of the study was to review the literature regarding the outcomes of older patients treated for pancreatic cancer, including the usage of minimal invasive techniques.
Methodology: A review of the literature was carried out including studies on pancreatic cancer in older patients published between 2011 and 2016.
Results: Seventeen retrospective studies were included. The total number of patients was 9981 with the age range of 65 years and more. Studies on surgical treatment alone (1.4%), neoadjuvant/adjuvant treatment with or without surgery (89.4%) and palliative therapy (9.2%) were assessed separately. Appropriate comparison was diffi cult due to the retrospective character and heterogeneity of the study population. Mortality was low, yet there was a great diff erence in morbidity ranging from some percent to even 100% of the study population. Long-term results were poor.
Conclusions: The functional status, not the chronological age alone, is the factor limiting therapeutic options in older patients with pancreatic cancer.