Recently a new technology of piezoelectric transducers based on PZT thick film has been developed as a response to a call for devices working at higher frequencies suitable for production in large numbers at low cost. Eight PZT thick film based focused transducers with resonant frequency close to 40 MHz were fabricated and experimentally investigated. The PZT thick films were deposited on acoustically engineered ceramic substrates by pad printing. Considering high frequency and non-linear propagation it has been decided to evaluate the axial pressure field emitted (and reflected by thick metal plate) by each of concave transducer differing in radius of curvature - 11 mm, 12 mm, 15 mm, 16 mm.

All transducers were activated using AVTEC AVG-3A-PS transmitter and Ritec diplexer connected directly to Agilent 54641D oscilloscope. As anticipated, in all cases the focal distance was up to 10% closer to the transducer face than the one related to the curvature radius. Axial pressure distributions were also compared to the calculated ones (with the experimentally determined boundary conditions) using the angular spectrum method including nonlinear propagation in water. The computed results are in a very good agreement with the experimental ones. The transducers were excited with Golay coded sequences at 35-40 MHz. Introducing the coded excitation allowed replacing the short-burst transmission at 20 MHz with the same peak amplitude pressure, but with almost double center frequency, resulting in considerably better axial resolution. The thick films exhibited at least 30% bandwidth broadening comparing to the standard PZ 27 transducer, resulting in an increase in matching filtering output by a factor of 1.4-1.5 and finally resulting in a SNR gain of the same order.

The paper presents the theoretical and experimental study of synthetic transmit aperture (STA) method combined with Golay coded transmission for medical ultrasound imaging applications. The transmission of long waveforms characterized by a particular autocorrelation function allows to increase the total energy of the transmitted signal without increasing the peak pressure. It can also improve signal-to-noise ratio and increase the visualization depth maintaining the ultrasound image resolution.

In the work the 128-element linear transducer array with 0.3 mm pitch excited by the 8 and 16-bits Golay coded sequences as well as a one cycle at nominal frequencies 4 MHz were used. The comparison of 2D ultrasound images of the tissue mimicking phantoms is presented to demonstrate the benefits of coded transmission. The image reconstruction was performed using synthetic STA algorithm with transmit and receive signals correction based on a single element directivity function.

The paper refers to previous publications of the author, focused on criteria of casting feeding, including the thermal criterion proposed by

Niyama. On the basis of this criterion, present in the post-processing of practically all the simulation codes, danger of casting compactness

(in the sense of soundness) in form of a microporosity, caused by the shrinkage phenomena, is predicted. The vast majority of publications

in this field concerns shrinkage and feeding phenomena in the cast steel castings – these are the alloys, in which parallel expansion

phenomenon does not occur as in the cast irons (graphite crystallization). The paper, basing on the simulation-experimental studies,

presents problems of usability of a classic, definition-based approach to the Niyama criterion for the cast iron castings, especially of

greater massiveness, for prediction of presence of zones of dispersed porosity, with relation to predictions of the shrinkage type defects.

The graphite expansion and its influence on shrinkage compensation during solidification of eutectic is also discussed.

The validation of each simulation code used in foundry domain requires individual approach due to its specificity. This validation can by

elaborated on the basis of experimental results or in particular cases by comparison the simulation results from different codes. The article

concerns the influence of grey cast iron density curve and different forms of solid fraction curve Fs=f(T) on the formation of shrinkage

discontinuities. Solid fraction curves applying Newtonian Thermal Analysis (NTA) were estimated. The experimental and numerical

simulation tests were performed on the castings, which were made with Derivative Thermal Analysis (DerTA) standard cups. The

numerical tests were realized using NovaFlow&Solid (NF&S), ProCast and Vulcan codes. In this work, the coupled influence of both

curves on the dynamics of the shrinkage-expansion phenomena and on shrinkage defects prognosis in grey cast iron castings has been

revealed. The final evaluation of the simulation systems usefulness should be based on validation experiment, preceded by comparing the

simulation results of available systems which are proposed in given technology.

The article presents basic changes introduced in the first edition of the governmental Urban Planning and Building Code. The changes regard spatial development, especially planning and permit documents, and competences of the governmental bodies in accepting, legislating and issuing such documents. In this respect, the article points out important regulations for the mining industry, in particular for deposit protection and the initiation of mining projects. In certain cases, critical opinions of some of the governmental institutions are mentioned. In a new document regarding the “Spatial Development Study of a Community”, the draft of the Code orders a division of the community into functional zones. Therefore a mining and extractive industry could be delimited as a functional zone. The Code also specifies that while delimiting a new urbanization area, the documented mining deposits areas should be avoided. In relation to the local spatial plan, the Code establishes the following: in documented strategic mining deposit zones the initiation of non-public purpose investments can only be carried out according to the urban spatial plan. This project also orders that only the local spatial plan can allow for the localization of “establishments that carry a risk of serious industrial breakdown” and “investments that can seriously impact the environment”. The Code also introduces another innovation: the possibility of issuing the local spatial plan with an integrated evaluation on the environmental impact. The “investment permits” are intended to replace both the previous building permits and previous decisions on the conditions of development of the areas not covered in the local spatial plans. The investment permits referring to mining establishments will be issued by the mining administration authorities. The main adverse change for mining is that the exploration of mining deposits owned by the State Treasury loses its previous status of public purposes. The article also indicates that some of the described regulations might be changed during the further legislation process.

The presented article contains an analysis resulting from 10 years’ experience in the implementation of the POLVAL Code to mineral assets valuations carried out by Competent Valuators. It had been based on data of more than 100 performed valuations. First and foremost, challenges resulting from preferences given by various relevant regulations to the application of a market-based approach were identified. It was underlined that they prompt Valuators to compromise the quality of the database containing reference transactions. In the case of an income based approach, issues resulting from the adoption of estimates and subjective assumptions were discussed. It was indicated that this fact alone cannot create a valid argument to reject the results of such a valuation providing that they have been implemented in a coherent manner and uncertainty was reflected in the value of the applied discount rate. Separately recommended changes to the present version of the POLVAL Code were presented. In conclusion, a significant, positive role of the introduction of the POLVAL Code for the structuring processes of mineral asset valuation was indicated.

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 early days, consumption of multimedia content related with audio signals was only possible in a stationary manner. The music player was located at home, with a necessary physical drive. An alternative way for an individual was to attend a live performance at a concert hall or host a private concert at home. To sum up, audio-visual effects were only reserved for a narrow group of recipients. Today, thanks to portable players, vision and sound is at last available for everyone. Finally, thanks to multimedia streaming platforms, every music piece or video, e.g. from one’s favourite artist or band, can be viewed anytime and everywhere. The background or status of an individual is no longer an issue. Each person who is connected to the global network can have access to the same resources. This paper is focused on the consumption of multimedia content using mobile devices. It describes a year to year user case study carried out between 2015 and 2019, and describes the development of current trends related with the expectations of modern users. The goal of this study is to aid policymakers, as well as providers, when it comes to designing and evaluating systems and services.

Simplifications used in simulation program codes require the use of substitute parameters in the material databases (also called apparent or substitutive). On the one hand, they formally fit into the records used in the heat flow model, porosity, properties etc. and on the other hand they should be determined in conditions most similar to the real casting-mould system.

The article presents results of a research on thermophysical parameters of gypsum mould used for precision casting moulds. Experiments were carried out on a cylindrical mould made of Plasticast gypsum, in which the heat source was a cylinder filled with liquid aluminium alloy of the temperature of 655°C. Energetic validation was carried out by using the NovaFlow&Solid ver. 6.3 simulation code. As a result of validation tests, substitute thermophysical parameters of gypsum were determined. For determined parameters, best-fit of solidification time from the experiment and simulation was obtained and the curves of gypsum mass heating were satisfactorily recreate.

Arriving at a good combination of coding and modulation schemes that can achieve good error correction constitutes a challenge in digital communication systems. In this work, we explore the combination of permutation coding (PC) and pulse amplitude modulation (PAM) for mitigating channel errors in the presence of background noise and jitter. Since PAM is characterised with bi-polar constellations, Euclidean distance is a good choice for predicting the performance of such coded modulation setup. In order to address certain challenges facing PCs, we therefore introduce injections in the coding system, together with a modified form of PAM system. This modification entails constraining the PAM constellations to the size of the codeword’s symbol. The results obtained demonstrate the strength of the modified coded PAM system over the conventional PC coded PAM system.