This paper addresses the state-variable stabilising control of the power system using such series FACTS devices as TCPAR installed in the tie-line connecting control areas in an interconnected power system. This stabilising control is activated in the transient state and is supplementary with respect to the main steady-state control designed for power flow regulation. Stabilising control laws, proposed in this paper, have been derived for a linear multi-machine system model using direct Lyapunov method with the aim to maximise the rate of energy dissipation during power swings and therefore maximisation their damping. The proposed control strategy is executed by a multi-loop controller with frequency deviations in all control areas used as the input signals. Validity of the proposed state-variable control has been confirmed by modal analysis and by computer simulation for a multi-machine test system.

Antarctic krill carbohydrate content was followed during 1983—84 Eighth Polish Antarctic Expedition. The Admiralty Bay (King George Island) was th area of study. The following average values of three estimated fractions were obtained: 3.77 +- 1.51%, 0.47 +- 0.34% and 3.30 +- 1.33% for total, TCA-soluble and TCA-insoluble carbohydrates, respectively. Percentage contribution of the estimated fractions to dry weight varied seasonally (1.48—7.41%, 0.15—1.83%, and 1.28—6.28%, respectively). The carbohydrate content showed a clearcut cycle of changes over the calender year, with a minimum in autumn-winter and a maximum in spring-summer.

The manuscript presents the research results concerning the properties of concrete with non-clinker, low-emission binder composed of by-products from metallurgy and power industry: ground granulated blast furnace slag and fly ash from circular fluidized-bed combustion of brown coal. The binder was added in five proportions. The consistency and air content of the concrete mix were measured, as well as the temperature of the concrete mix during hardening. The compressive strength of the hardened concrete was investigated in three periods of samples’ curing: after 28, 90 and 360 days. Also the penetration depth of water under pressure and freeze and thaw resistance of concrete samples were investigated. The results confirm the possibility of application of slag-CFBC fly ash binder for mass concrete due to low temperature during hardening. The obtained results of the compressive strength and penetration depth of water under pressure reveal the influence of changing the proportion of the binder ingredients, as well as the sample damage during testing the freeze/thaw resistance. The CFBC fly ash-slag binder can be used for mass concrete, hydrotechnical concretes in particular, but excluding the zones exposed to frost.

In this work we discuss 3D selfconsistent solution of Poisson and Schrödinger equations for electrostatically formed quantum dot. 3D simulations give detailed insight into the energy spectrum of the device and allow us to find values of respective voltages ensuring given number of electrons in the dot. We performed calculations for fully 3D potential and apart from that calculations for the same potential separated into two independent parts, i.e. regarding to the plane of 2DEG and to the direction perpendicular to the meant plane. We found that calculations done for the two independent parts of the potential give good information about quantum dot properties and they are much faster compared to fully 3D simulations.

Strength and permeability properties along with microstructural evolution of hardened slurries composed of fly ash from fluidal bed combustion of brown coal and an addition of OPC/BFSC is assessed in this paper. An increase in the amount of fly ash in slurries influences the development of mechanical strength and a decrease of hydraulic conductivity. SEM, XRD, and porosity analyses confirmed formation of watertight microstructures. The structure of slurries is composed of ettringite, C-S-H phase, AFt, and AFm phases. Ettringite crystallises as relatively short needles forming compact clusters or intermixed with the C-S-H phase. The occurring C-S-H phases are mainly of type I – fibrous and type II – honeycomb

The manuscript presents the condition of circular economy in Poland in diversified approach: subjective (waste streams, energy), sectoral (construction, wastewater treatment, coal energy), related to the resources (phosphorous and anthropogenic minerals) and considering proper energy management (almost zero energy buildings). The achievements reached in different sectors as well as the requirements towards implementation of CE are presented. The advancement of recycling technologies does not deviate from the global level, in terms of areas specific to Poland. Limiting the exploitation of natural resources and usage of new materials as well as producing more durable products are of CE concern. Also energy and heat recovery in buildings and technological processes (e.g. during wastewater treatment), ways of utilization of combustion by-products and water decarbonization waste are described. The implementation of CE in Poland needs not only research and technical activities, but also the modification of technological processes, the right policy, overcoming crosssectoral barriers, developing legal regulations and support schemes for CE.

Cut-off walls built using self-hardening slurries are an important tool for modern engineering pursuing Sustainable Development Goals. Much like cement concrete, this material is affected by the challenges posed by the increasing human pressure on the environment, although it is used significantly less widely than concrete; for this reason, relatively little comprehensive literature data is available describing the interaction of self-hardening slurries with the environment. This article provides a review that complements the current state of knowledge on self-hardening slurries in this area, with a particular focus on the durability of the material and its pollutant immobilization capabilities. To provide context, the material’s operating conditions, properties and components are briefly characterized. The resistance of self-hardening slurries to environmental aggression is described extensively, as it is a key factor in ensuring the durability of the material. A sample analysis of the material’s carbon footprint in several representative composition variants is presented. The subject of pollutant immobilization by self-hardening slurries is outlined. Lines of further research are proposed to fill gaps in the available knowledge.