This paper addresses weighted L2 gain performance switching controller design of discrete-time switched linear systems with average dwell time (ADT) scheme. Two kinds of methods, so called linearizing change-of-variables based method and controller variable elimination method, are considered for the output-feedback control with a supervisor enforcing a reset rule at each switching instant are considered respectively. Furthermore, some comparison between these two methods are also given.

Traditional methods of mineral exploration are mainly based on very expensive drilling and seismic methods. The proposed approach assumes the preliminary recognition of prospecting areas using satellite remote sensing methods. Maps of mineral groups created using Landsat 8 images can narrow the search area, thereby reducing the costs of geological exploration during mineral prospecting. This study focuses on the identification of mineralized zones located in the southeastern part of Europe (Kosovo, area of Selac) where hydrothermal mineralization and alterations can be found. The article describes all the stages of research, from collecting in-situ rock samples, obtaining spectral characteristics with laboratory measurements, preprocessing and analysis of satellite images, to the validation of results through field reconnaissance in detail. The authors introduce a curve-index fitting technique to determine the degree of similarity of a rock sample to a given pixel of satellite imagery. A comparison of the reflectance of rock samples against surface reflectance obtained from satellite images allows the places where the related type of rock can be found to be determined. Finally, the results were compared with geological and mineral maps to confirm the effectiveness of the method. It was shown that the free multispectral data obtained by the Landsat 8 satellite, even with a resolution of 30 meters, can be considered as a valuable source of information that helps narrow down the exploration areas.

The article examines two Aramaic contracts found on the island Elephantine and dating from the early fifth century B.C. The first one is a loan contract providing for payment of compound interest on silver lent: interest not paid timely is to be added to the capital and itself becomes interest-bearing at the same rate until actual repayment. If this is not done at an agreed date, the remaining debt is doubled. The second contract concerns delivery of barley and lentils from a ship to a royal store-house deserving a garrison. The parties are the ship-officer and functionaries acting on behalf of the store-house, where barley and lentils are supposed to be brought. It is a contract of delivery combining its acceptation on the ship and the foreseen completion of the contract in the store-house with expected financial results. Both contracts refer to silver “by the stone-weights of Ptah” and record its alloy.

Fly ash which has been separated from the flue gas stream as a result of fossil fuels combustion constitutes a huge amount of waste generated worldwide. Due to environmental problems, many directions of their rational use have been developed. Various attempts to convert fly ash into sorption materials, mainly synthetic zeolites, are conducted successfully. In this paper, an attempt was made to convert fly ash from lignite combustion from one of the Polish power plants, using alkaline hydrothermal synthesis. The primary phases in the fly ash were: quartz, gehlenite, mullite, hematite, feldspar, lime, anhydrite, occasionally grains of ZnO phase and pyrrhotite, glass and unburned fuel grains. As a result of hydrothermal synthesis a material containing new phases – pitiglianoite and tobermorite was obtained. Among the primary ash constituents, only gehlenite with an unburned organic substance, on which tobermorite with crystallized pitiglianoite was present. As a result of detailed testing of products after synthesis, it was found that among the tested grains:

• two populations can be distinguished – grains containing MgO and Fe2O3 as well as grains

containing Fe2O3 or MgO or containing none of these components,

• the main quantitative component was pitiglianoite,

• pitiglianoite was present in larger amounts in grains containing Fe2O3 or MgO or in the absence of both components than in grains in which Fe2O3 and MgO were found.

The results of the study indicate that in post-synthesis products, the contribution of components were as follows: pitiglianoite – 39.5% mas., tobermorite – 54% mas., gehlenite – 3% mas. and organic substance – 3.5% mas.

In the article there was described the current state of mines against a background of tradition of exploitation and application of rock raw materials. Active quarries were selected, where the extraction of rock blocks has been a tradition, as well as quarries where the geological structure of the deposit allows to exploit the blocks in the future. There were also assessed old quarries and their deposits where the popular stones had been extracted in the past and then used in domestic architecture as a decorative materials. That is a group of more than 230 deposits in total. It has been presented economically justified perspectives of exploitation development concerning decorative and architectural rocks in south-eastern Poland against a background of European market requirements, the state of resources and environmental limitations. It was established that they are differentiated depending on the decorative properties of the rocks, their block divisibility and quantity of resources. Taking above-mentioned into consideration the deposits have been classified to groups which have the chances of exploitation development in the European, domestic and local scale. The former are Zygmuntówka Conglomerate, Morawica Limestone, Zalesiaki Limestone and Diplopora Dolomite. The domestic scope of use can be associated with properly developed deposits of Paleozoic limestones in the vicinity of Kielce and Krzeszowice and some dimension sandstones in the margin of the Holy Cross Mountains and in the Carpathians. The small deposits of sandstones from the Holy Cross Mountains margin and from the Carpathians as well as deposits of limestones from the Kraków-Częstochowa Upland, excavating material used in so called small architecture, have guarantee of local development. Moreover there was shown the hazard to the dimension stones deposits connected with the huge consumption of their resources for the production of crushed aggregates. This problem concerns especially raw materials with good physico-mechanical properties. For the most attractive rocks it was justified the need of their protection against exploitation for the other purposes than block production. It was stated that the return to local masonry traditions is possible and necessary because of many connections with the national culture through its history, architecture and art. It requires large investments for modernize the exploitation methods as well as for promotion of Polish stones in the European market. It must be also taken into consideration the possibility of financial support from the European Union funds.

Several surface measurement methods for determining the volume of deep or layered stone exist.

One of the key indicators of coal extraction efficiency in open cast mining is to determine the volume

of excavated rock. Procedures for determining the volume have been used for many centuries.

Determining the extracted volume or layered material has been a periodically recurring role of mine

-surveying practice, and mine surveyors apply different methods for its determination. The incorrect

determination of the rock volume may result in large economic losses of the mining enterprise. The

choice of the method for determining the volume depends on the deadline by which the determined

volume has to be submitted to the superior components or the mining enterprise management, as well

as on the requirements for accuracy of the volume determination, and a financial limit beyond which

this volume determination has to be done. Secondary conditions for determining the volumes include

the level of personnel training in the individual procedures and methods of measuring and calculating

volumes, the technical standards of the enterprise, the applied instrumentation, hardware and

software. The article compares the values of the accurately defined mathematical solid (a cylindrical

segment) to the methods of calculating the volume normally used in mining and surveying practice

and programs commonly used to calculate volumes in order to determine the threshold value of the

systematic deviation in input measurements to determine the volume. The mathematical model is the

basis for determining the correct volumes of the extracted material. The surface of the drawn or layered

material does not form a smooth surface as a mathematical model. The process of determining

volume errors on the mathematical model has been verified on the real body of coal deposition. The

comparison of the determination of the errors between the digital terrain model on the mathematical

body and the real homogenization coal stock is presented at the Conclusion of the article.