The paper presents an overview of scaling models used for determining hydrodynamic parameters of Circulating Fluidized Bed boilers. The governing equations and the corresponding dimensionless numbers are derived and presented for three different approaches to the scaling law of fluidized beds: classical dimensional analysis, differential equations and integrated solutions and experimental correlations. Some results obtained with these equations are presented. Finally, the capabilities and limitations of scaling experiments are discussed.
In this paper we discuss the test results for concretes containing various amounts of ggbs as compared to concretes made with Portland cement. The main objective of these tests is to evaluate the influence of varying air content in such mixtures on the structure and frost resistance of concrete. The authors suggest that the approach presented here allows for a safe design of concrete mixtures in terms of their frost resistance.
The results indicate that concrete can be resistant to surface scaling even at the W/C ratio markedly higher than 0.45. Increased addition of ggbs leads to a decrease in concrete resistance to surface scaling. Proper air entrainment is the fundamental factor for frost-resistant concrete, and the air void system has to be assessed (micropore content A₃₀₀, spacing factor L). The addition of ggbs increases pore diameters, thus, to obtain the appropriate air pore spacing factor, micropore quantities introduced have to be increased.
The article presents the results of laboratory tests carried out on a scaling model of the 966MWth fluidised-bed boiler operating in the Lagisza Power Plant, made on a scale of 1:20 while preserving the geometrical similarity. The tests were carried out for scaled-down material taken from different locations on the circulation contour in the state of full boiler loading. To reflect the hydrodynamic conditions prevailing in the combustion chamber, solids with properly selected density and particle size distribution were used. The obtained results have made it possible to determine the location for taking the most representative granular material sample.
The paper presents the results of model studies on the hydrodynamics of the world's first supercritical circulating fluidized bed boiler Lagisza 460 MWe, carried out on a scale model built in a scale of 1/20 while preserving the full geometrical similarity. To reflect the macroscopic pattern of flow in the boiler's combustion chamber, tests were carried out based on two dimensionless flow dynamic similarity criteria, while maintaining a constant Froude number value between the commercial and the scaled-down units. A mix of polydispersion solids with its fractional composition determined by scaling down the particle size distribution of the boiler's inert material was utilised for the tests using a special scaling function. The obtained results show very good agreement with the results of measurements taken on the Lagisza 460 MWe supercritical CFB boiler.
The paper presents a scaling approach to the analysis of coercivity. The Widom-based procedure of coercivity scaling has been tested for non-oriented electrical steel. Due to insufficient results, the scaling procedure was improved relating to the method proposed by Van den Bossche. The modified procedure of coercivity scaling gave better results, in comparison to the original approach. The influence of particular parameters and a range of measurement data used in the estimations on the final effect of the coercivity scaling were discussed.
In the paper flow dynamic similarity criteria have been presented to reflect the macroscopic flow pattern in the combustion chamber of large-scale circulating fluidised bed boilers. The proposed scaling rules have been verified on two cold models of CFB boilers operating in Tauron Wytwarzanie S.A. - El. Lagisza division (scale factor 1/20) and Fortum Power and Heat Poland Sp. z o. o. Czestochowa division (scale factor 1/10) – working with the power of 966 MWth and 120 MWth, respectively. As follows from the results of measurements, regardless of CFB boiler’s geometry the use of a defined set of criterial numbers allows to obtain satisfactory agreement between the suspension density distributions registered in the CFB boilers and scaling models.
This study aimed to compare measures of religiosity and spirituality in the experience of positive and negative emotions. For this purpose, a measure of non-spiritual religiosity (Religious Sense Scale) was developed. Method: The study has been conducted on a sample of 279 participants aged between 19 and 69 (M=24.42, SD=9.463) who completed a questionnaire that included the Religious Sense Scale, the Portuguese version of the Spiritual Well-being Questionnaire and the abridged Portuguese version of the Positive and Negative Affect Schedule. Findings: The was found to have excellent metrical properties for the measurement of religiosity or “religious sense”. Religious individuals differ from spiritual ones in the experience of emotions: spirituality tends to a greater experience of positive affect and religiosity to negative affect.
This paper presents the results of a study on the Polish version of the Generic Conspiracist Beliefs Scale (GCBS), which was designed to measure individual differences in conspiracist thinking (Brotherton, French, & Pickering; 2013). The Polish version of the scale had excellent internal consistency as measured by Cronbach alpha: .93. The Polish version also had excellent test-retest stability. To check the validity of the questionnaire, various tools were used to measure the characteristics that can be correlated with conspiracist thinking. As a result, it was found that conspiracist thinking is positively correlated with the external locus of control, the results obtained in the Scale of Belief in Zero-Sum Game and the results of the MMPI-2 Paranoia scale. It was also found that patients with paranoid personality disorder and paranoid schizophrenia had higher results on the adapted scale than healthy subjects. In sum, the Polish version of GCBS had satisfactory psychometric properties, which makes it useful for measuring conspiracist thinking.
The main goal of this research study is focused on creating a method for loudness scaling based on categorical perception. Its main features, such as: way of testing, calibration procedure for securing reliable results, employing natural test stimuli, etc., are described in the paper and assessed against a procedure that uses 1/2-octave bands of noise (LGOB) for the loudness growth estimation. The Mann-Whitney U-test is employed to check whether the proposed method is statistically equivalent to LGOB. It is shown that loudness functions obtained in both methods are similar in the statistical context. Moreover, the band-filtered musical instrument signals are experienced as more pleasant than the narrow-band noise stimuli and the proposed test is performed in a shorter time. The method proposed may be incorporated into fitting hearing strategies or used for checking individual loudness growth functions and adapting them to the comfort level settings while listening to music.
The results of the eddy currents losses calculations with using electrodynamics scaling were presented in this paper. Scaling rules were used for obtain the values of the eddy currents losses. For the calculations Finite Element Method was used. Numerical calculations were verified by measurements and a good agreement was obtained.
Vertical distribution and quantitative and qualitative phytoplankton composition were studied in Ezcurra Inlet, Admiralty Bay, South Shetland Islands in the austral summer 1977/78. Nannoplankton flagellates, 12—15 μm in diameter and 4—6 μm "monads" were the principal algae of the plankton. Diatoms, present in a low abundance, were dominated by Thalassiosira antarctica and several species of the genera Nitzschia and Chaetoceros. Peaks of cell numbers within the 1—10 m surface stratum and at the bottom of the euphotic zone were characteristic of the vertical distribution of phytoplankton. Light, water movements and density micro-gradients were the likely factors controlling the vertical distribution of algae.
Liquid-liquid extraction provides an environmentally friendly process as an alternative to azeotropic distillation, pervaporation and reverse osmosis because these techniques require the use of large amounts of energy, may involve volatile organic compounds, and operation at high pressure.
Ionic liquids (ILs) continue to gain wide recognition as potential environmentally friendly solvents due to their unique properties. However due to their current high cost, their use in industry is seriously limited without an efficient methodology for recovery and recycle.
In this paper we describe an innovative methodology for a liquid-liquid extraction process based on an electrically induced emulsion of an ionic liquid as the extracting solvent dispersed in an organic mixture. This offers a most efficient exploitation of the solvent. On the other hand we present our own design of a pilot (semi-industrial) scale extractor based on this methodology and which demonstrates effective recovery of the ionic liquid. In order to achieve this goal we used a numerical modelling tool implemented using our own simulation software based on the finite element method. We also used our original previous experience with generating and investigating liquid-liquid electrosprays using phase Doppler anemometry. Finally we present recommendations for contactor geometry and for the preferred operating conditions for the extractor.
Re-design of a given antenna structure for various substrates is a practically important issue yet non trivial, particularly for wideband and ultra-wideband antennas. In this work, a technique for expedited redesign of ultra-wideband antennas for various substrates is presented. The proposed approach is based on inverse surrogate modeling with the scaling model constructed for several reference designs that are optimized for selected values of the substrate permittivity. The surrogate is set up at the level of coarse-discretization EM simulation model of the antenna and, subsequently, corrected to provide prediction at the high-fidelity EM model level. The dimensions of the antenna scaled to any substrate permittivity within the region of validity of the surrogate are obtained instantly, without any additional EM simulation necessary. The proposed approach is demonstrated using an ultra-wideband monopole with the permittivity scaling range from 2.2 to 4.5. Numerical validation is supported by physical measurements of the fabricated prototypes of the re-designed antennas.
The paper is focused on the main problems of modern metrology in the context of the Fourth Industrial Revolution “Industry 4.0”, particularly in the field of qualimetry. The dominant issues of the methodology of qualimetrical measurement, as the interrelation between metrology and qualimetry, are considered. The following questions are raised and analysed: determination of the measurand in the qualimetrical measurement, creation of the virtual product quality pattern, determination of the product quality level by using the theory of multidimensional scaling, assurance of the metrological traceability of the qualimetrical measurement results. A procedure of performing the qualimetrical measurement is described.
In a series of recent papers we have shown how the continuum mechanics can be extended to nano-scale by supplementing the equations of elasticity for the bulk material with the generalised Young-Laplace equations of surface elasticity. This review paper begins with the generalised Young-Laplace equations. It then generalises the classical Eshelby formalism to nano-inhomogeneities; the Eshelby tensor now depends on the size of the inhomogeneity and the location of the material point in it. The generalized Eshelby formalism for nano-inhomogeneities is then used to calculate the strain fields in quantum dot (QD) structures. This is followed by generalisation of the micro-mechanical framework for determining the effective elastic properties of heterogeneous solids containing nano-inhomogeneities. It is shown that the elastic constants of nanochannel-array materials with a large surface area can be made to exceed those of the non-porous matrices through pore surface modification or coating. Finally, the scaling laws governing the properties of nano-structured materials are given.
Industrial utilization of fly ash from various kinds of fuel plays an important role in the envi-ronmentally clean and cost effective power production. The primary market for fly ash utilizationis as a pozzolanic addition in concrete production. The paper concerns the concretes containingfly ash called Fly Ash from Biomass (FAB) from co-combustion of hard coal and wood biomass(wood chips). Characterization of the fly ash was carried on by means of X-ray diffractometryand E-SEM/EDS analysis. The results of laboratory studies undertaken to evaluate the influence of FAB on concrete resistance to surface scaling due to cyclic freezing and thawing in the presenceof NaCl solution were presented. The tests were carried out for concretes containing up to 25% offly ash related to cement mass. Additionally, the microstructure of air-voids was described.
It was concluded that the FAB has significant effect on concrete freeze/thaw durability. The re-placement of cement by fly ash from co-combustion progressively transformed the concrete mi-crostructure into less resistant against freeze/thaw cycles and excessive dosage (over 15%) maydangerously increase the scaling.
The transformation of the former docks in Dublin was one of the major urban regeneration projects in Ireland, which was built during the recent economic boom. Since the start of the project in the nineties, more than six thousand apartments have been built in the area. The construction of the apartments allowed for the diversifi cation of the character of this district into a living quarter. Initially the Docklands were considered as an offi ce district that would serve the Ireland’s service-based economy. New projects also allowed for the development of housing in a close proximity to existing city centre, although it did not happen not without avoiding the gentrifi cation and social polarization of this area.
The key role in the process was played by the operator – the urban development agency (Dublin Docklands Development Authority). It acted both as a strategic landowner and the coordinator of the development. The agency was responsible for the delivery of the infrastructure and the sale of the land. The actions of the operator included setting up the of the housing standards, requirements for the development of the infrastructure, both social and technical and public transportation systems. In the hindsight, the agency was praised for the management of the development of such large site. On the other hand, the lack of procedural oversight and a few dubious fi nancial decisions, as well as the other eff ects of the neoliberal policies, such as gentrification, fi nally lower the assessment of DDDA efficiency in that matter.
The article summarizes the main aims and achievements of the DDDA’s development policy and its assessment from the long-term perspective of two decades of transformation. This includes the eff ects of the actions in the aftermath of the fi nancial crisis. Such perspective allows to highlight the various stages of the development of the agency and to examine the efficiency and efficacy of these actions.