The hereby paper discusses the influence of cable length on the SHM systems with the use of vibrating wire dynamic measurements. Vibrating wire sensors are mainly used for measuring stable or slowly changing strains, e.g. system installed on Rędziński Bridge in Wroclaw. From some time applications of these sensors for measuring dynamic deformations are becoming popular. Such tests were conducted on STS Fryderyk Chopin. New solutions generate new problems. In this case: the operational stability of systems exciting wire vibrations. The structure of such sensors and the electric cables length has an essential influence on their operations, what is undertaken in the paper. The subject of investigations constitutes the measuring system based on self-exciting impulse exciter, for which impedance parameters of electric cables and of the vibrating wire sensor were the most essential. The mathematical model of the system, experimental verification of the model as well as the results of theoretical analyses at the application of electric cables of various lengths are presented in the paper.
Research on the chemistry of atmospheric precipitation in the Hornsund region of Svalbard has been extended by analysis of the organic contents. In rainfall samples collected in September 2003, the organics were separated by solid phase extraction (SPE), eluted and analysed on gas chromatograph coupled to a mass selective detector (GC/MS). Rainfall pH was in the range 4.72–5.45, the low values suggesting possible pollution. Concentrations of inorganic ions, expressed as total dissolved salts (TDS), were 5.40–13.18 mg L–1. Non-sea-salt (nss) sulphates were in the range 5–11 μeq L–1. In all samples, long-chain alkanes with chain length up to C36, and their methyl derivatives were detected. Among aromatic compounds biphenyl, dibenzofuran and its methyl derivatives were found. Polycyclic aromatic hydrocarbons (PAHs) were represented by naphthalene, phenanthrene, fluorene, acenaphthene, fluoranthene and pyrene. There were no PAHs with higher numbers of rings. The synoptic meteorological conditions in September 2003 indicate that all organic and inorganic pollutants were of local origin.
The aim of the article is to diagnose the regional diversification of development in the axiological context. The starting point in this analysis is the term: development. This category is understood in a multidimensional manner. Presented in this paper conceptual model of development allows to distinguish three levels of analysis of the development process: material, social and cultural. Identification of the axiological phenomenon of the diversification of regional development in this research is ultimately served by the systematization tool – typology, introducing the division into the culture of honour, achievements and joy.
Over the past decade, the growing demand for imported coal from consumers (mainly Asian) coincided with supply constraints on the part of major suppliers. The sequence of events is referred to as force majeure. There were many events in the exporting countries, mainly including the cyclone and floods in Australia (Queensland, the world’s largest hard coking coal mining region). Imbalance between supply and demand causes commodity prices to be subject to cyclical changes, but in recent years the frequency and dynamics of these changes in the international metallurgical market (hard coking coal, semi-soft coking coal, PCI coal) has been extremely high. China, the world’s largest producer and consumer of coking coal, played a leading role in these events. Political action by the Chinese authorities regarding their domestic mining and metallurgical industries and the coke-chemical industry has made the country dethrone Japan since 2013 and has become a global leader in metallurgical coal imports. The rise of China’s importance in coal trading has become an important benchmark for monitoring market trends and benchmarking benchmarks. The market has become more bipolar and CFR China’s prices (in addition to Australia’s FOB prices). The paper describes the path of pricing mechanism changes in international trade contracts for metallurgical coal, against the background of market conditions that generate these changes.
The concept of “places of refuge ” comes from the Convention on Maritime Safety of 1989. The term “port of refuge” had emerged earlier in maritime practice. Resolution A.949/23/ o f the General Assembly of the IMO, from 5 December 2004, speaks of “places of refuge” for ships in need of help. Directive 2002/59/WE o f the European Parliament and Council, setting up a community system of monitoring and of information on the movement of vessels, and abrogating Council Directive 93/75/EWG, introduced places of refuge, drawing on the “Guidelines ” of the IMO. IMO Resolution A.949/23/ became the legal norm valid in Member States. The decree of the Polish Minister for Maritime Economy from 14 September 2007, as executive implementation of legislation of 20 April 2004, concerning a change of legislation in the matter of maritime safety, sets out a plan for offering refuge in Polish maritime waters to vessels that find themselves in danger. The author accepts that a place of refuge may be a natural spot that is appropriate for this purpose, and also a place specially constructed for vessels in danger. It may also be an existing port or part of one.
Vibrating plates have been recently used for a number of active noise control applications. They are resistant to difficult environmental conditions including dust, humidity, and even precipitation. However, their properties significantly depend on temperature. The plate temperature changes, caused by ambient temperature changes or plate heating due to internal friction, result in varying response of the plate, and may make it significantly different than response of a fixed model. Such mismatch may deteriorate performance of an active noise control system or even lead to divergence of a model-based adaptation algorithm.
In this paper effects of vibrating plate temperature variation on a feedforward adaptive active noise reduction system with the multichannel Filtered-reference LMS algorithm are examined. For that purpose, a thin aluminum plate is excited with multiple Macro-Fiber Composite actuators. The plate temperature is forced by a set of Peltier cells, what allows for both cooling and heating the plate. The noise is generated at one side of the plate, and a major part of it is transmitted through the plate. The goal of the control system is to reduce sound pressure level at a specified area on the other side of the plate.
To guarantee successful operation of the control system in face of plate temperature variation, a gain-scheduling scheme is proposed to support the Filtered-reference LMS algorithm.
In this study the authors minimise the total process cost for the heating of solid particles in a horizontal fluidised bed by an optimal choice of the inlet heating gas temperature profile and the total gas flow. Solid particles flowed along the apparatus and were heated by a hot gas entering from the bottom of the fluidised apparatus. The hydrodynamics of the fluidised bed is described by a two-phase Kunii - Levenspiel model. We assumed that the gas was flowing only vertically, whereas solid particles were flowing horizontally and because of dispersion they could be additionally mixed up in the same direction. The mixing rate was described by the axial dispersion coefficient. As any economic values of variables describing analysing process are subject to local and time fluctuations, the accepted objective function describes the total cost of the process expressed in exergy units. The continuous optimisation algorithm of the Maximum Principle was used for calculations. A mathematical model of the process, including boundary conditions in a form convenient for optimisation, was derived and presented. The optimization results are presented as an optimal profile of inlet gas temperature. The influence of heat transfer kinetics and dispersion coefficients on optimal runs of the heating process is discussed. Results of this discussion constitute a novelty in comparison to information presented in current literature.
This paper presents a novel strategy of particle filtering for state estimation based on Generalized Gaussian distributions (GGDs). The proposed strategy is implemented with the Gaussian particle pilter (GPF), which has been proved to be a powerful approach for state estimation of nonlinear systems with high accuracy and low computational cost. In our investigations, the distribution which gives the complete statistical characterization of the given data is obtained by exponent parameter estimation for GGDs, which has been solved by many methods. Based on GGDs, an extension of GPF is proposed and the simulation results show that the extension of GPF has higher estimation accuracy and nearly equal computational cost compared with the GPF which is based on Gaussian distribution assumption.