Where abstraction meets reality.

This paper presents an analysis and simulation studies of three-phase matrix converter with GaN HEMT bidirectional switches with predictive control of grid currents and converter output currents. Two methods of grid currents shaping are described and compared. The first method is based on calculations of instantaneous grid reactive power and the second one uses the active power of the load. The analyzed converter works with the resistive-inductive load, and from the grid side the LC filter with damping resistor has been used.

During the past several years big changes have been observed in waste water disposal, noticeable particularly in the improvement of water protection and sewage treatment. An important element of waste water disposal still requiring improvement is a low development of sewage systems in rural and urban areas. The main problem is an increasing amount of sludge, high degree of sediment hydration and considerable ability to anaerobic decomposition, a lack of areas for managing sediments near big cities and deposits of sediments on storage areas. Selected issues of waste water disposal and sludge handling in the Mazovian Province against a background of waste water disposal and sludge handling in Poland were presented in the article.

Gdzie abstrakcja spotyka się z rzeczywistością.

Orhan Pamuk, the winner of the Nobel Prize in Literature in 2006, is one of the most interesting and versatile of contemporary writers whose prose contributes to the understanding of the cultural background of the Orient and the Occident forged out of the juxtaposition of Islam and Christianity. As a might-have-been artist, who is currently an amateur photographer, the author, in an uncommon way, visualizes the continual wonder towards colors in the surrounding reality featuring in his fictional and non-fictional texts. The most important aspects of Pamuk’s works, however, are the journeys near and far and those within oneself, as well as the wanderings through cities, especially those of his native Istanbul. Aside from the returns home and to the motherland, Pamuk contrasts the inspiring voyages out with the voyages into the collective and individual past, in all their historical and political complexity. The present paper is an overview of Orhan Pamuk’s works from the perspective of colors and the aforesaid passages, which remind his readers of travelling as a basic topos of the course of human existence.

The Vladimir Lenin Steelworks and other state-owned enterprises in Nowa Huta, the eastern district of Cracow, ran a number of holiday centres all over Poland and encouraged their staff to spend their leave in those places with their family members and colleagues. This form of organized leisure was also promoted by the press. So for example Głos Nowej Huty, a weekly issued by the Workers’ Council of the VL Steelworks, published articles showing the attractions and, occasionally, problems of individual holiday homes. At the same time readers were encouraged to file in their application in good time. The publicity contributed to the success of this type of organized leisure — the number of people who took up this offer increased year on year throughout that period.

Water is a strategic material. Recycling is an important component of balancing its use. Deep-bed filtration is an inexpensive purification method and seems to be very effective in spreading water recovery. Good filter designs, such as the fibrous filter, have high separation efficiency, low resistance for the up-flowing fluid and high retention capacity. However, one of the substantial problems of this process is the biofouling of the filter. Biofouling causes clogging and greatly reduces the life of the filter. Therefore, the melt-blown technique was used for the formation of novel antibacterial fibrous filters. Such filters are made of polypropylene composites with zinc oxide and silver nanoparticles on the fiber surface. These components act as inhibitors of bacterial growth in the filter and were tested in laboratory and full scale experiments. Antibacterial/bacteriostatic tests were performed on Petri dishes with E. coli and B. subtilis. Full scale experiments were performed on natural river water, which contained abiotic particles and mutualistic bacteria. The filter performance at industrial scale conditions was measured using a particle counter, a flow cytometer and a confocal microscope. The results of the experiments indicate a significant improvement of the composite filter performance compared to the regular fibrous filter. The differences were mostly due to a reduction in the biofouling effect.

Celem artykułu jest przedstawienie i analiza pojęcia ambiwalencji w kontekście badań socjologicznych, w tym eksploracji obszaru życia rodzinnego. Ambiwalencja to termin pochodzący z psychiatrii oraz psychoanalizy, spopularyzowany w socjologii przez Roberta K. Mertona i Elinor Barber. W tekście opisano sens pojęcia ambiwalencji w kontekście socjologii oraz ewolucję tej kategorii od ambiwalencji socjologicznej do ambiwalencji strukturalnej. Dodatkowo, autorka wykorzystuje kategorię ambiwalencji w analizie wyników badania praktyk rodzinnych i rodzicielskich, opisując dwa przykłady: ambiwalencję widoczną w zestawieniu oczekiwań rodziców wobec dzieci z codziennymi doświadczeniami dorosłych oraz ambiwalentny stosunek rodziców do urządzeń elektronicznych używanych przez dzieci. Podstawowe pytanie, które stawiane jest w artykule, brzmi: co nowego kategoria ambiwalencji wnosi do analiz prowadzonych w ramach socjologii życia rodzinnego.

Celem artykułu jest przedstawienie teorii praktyk oraz teorii praktyk rodzinnych i bazującej na niej koncepcji displaying families jako alternatywy dla prowadzenia badań w obszarze socjologii rodziny. Choć teorie praktyk oraz związana z nimi perspektywa doing families stanowią inspirację dla polskich badaczy rzeczywistości społecznej, to założenia teoretyczne tych koncepcji – zwłaszcza ich najbardziej aktualne wersje – rzadko są analizowane w sposób systematyczny. Dodatkowo, koncepcja displaying families jest mało znana jako metoda badawcza. Tymczasem, wydaje się że podejście inspirowane teoriami praktyk może być szczególnie cenne dla prowadzenia badań nad współczesnym życiem rodzinnym z co najmniej czterech powodów, które zostały opisane w ostatniej, trzeciej części artykułu. W pierwszej części tekstu przedstawiono analizę głównych założeń teorii praktyk, a w części drugiej – głównych założeń teorii praktyk rodzinnych oraz koncepcji displaying families.

Salinity has adverse effects on plants and is one of the causes of environment degradation. Plants have developed many defensive mechanisms, protecting them from sodium chloride (NaCl), including accumulation of osmoprotective compounds, which maintain osmotic balance, protect cell structure and enzymes. In the current study, we investigated the effects of salinity resulting from a range of sodium chloride concentrations (from 0 to 400 mM) on the growth of common duckweed (Lemna minor L.) and yellow lupin (Lupinus luteus L.). Increasing concentration of sodium chloride decreased the area of common duckweed leaves. At the highest applied salt concentration, the decrease of leaf area was associated with leaf chlorosis. In yellow lupin, the increasing sodium chloride concentration inhibited root and stem elongation. The highest tested NaCl concentration of 400 mM completely stopped elongation of yellow lupin shoots. The content of cyclitols and soluble carbohydrates in plant tissues was evaluated as well. Cyclitols (D -chiro -inositol and D -pinitol), as well as soluble carbohydrates (glucose, fructose and sucrose) were detected in common duckweed tissues. Yellow lupin seedlings also contained cyclitols - D -pinitol, myo -inositol and D -chiro -inositol - and soluble carbohydrates - glucose, galactose and sucrose. The content of osmoprotectants in plant tissues, especially sucrose and cyclitols, increased with increasing concentration of sodium chloride in the soil. The results indicate that the content of cyclitols and soluble carbohydrates in plant tissues can be an indicator of plant response to salinity stress.

One of the main problems of multivariable cost functions in model predictive control is the choice of weighting factors. Two finite control set model predictive control algorithms, applied to the three-phase active rectifier with an LCL filter, are described in the paper. The investigated algorithms, i.e. PCi_cu_c and PCi_gi_cu_c, implement multivariable approaches applying line (grid) current, capacitor voltage and converter current. The main problem dealt with in the paper is the choice of optimum values of the cost function weighting factors. The values of the factors calculated using the method proposed in the paper are very close to the values represented by the lowest THDi of the line current. Moreover, simulations verifying the equations used in the prediction of controlled values, i.e. line current, capacitor voltage and converter current, are presented. Both simulation and experimental results are presented to verify effectiveness of the investigated control strategies under change of the load (P = 5 kW and 2.5 kW), during transient states, under unbalanced and balanced line voltage.