The paper presents a certain way which determines the critical buckling force for a micro-heterogeneous FGM plate band. A stiffness matrix of an individual cell of such band, different for various cells, has been determined. The obtained matrix can also be treated as a variable stiffness matrix of a “superelement” in the Finite Element Method. A computational algorithm for the critical force as well as the way of testing of its correctness has also been presented. The results obtained for various support conditions have been compared to the values known from the literature. The influence of the number of cells on the critical buckling force has been investigated.

If we throw something into a river, how long will it take to reach a certain location downstream? We talk to Prof. Ian Guymer from the University of Sheffield about our increasingly complex models of this deceptively simple problem.

The problem of determining displacements of objects is an important and current issue, in particular in terms of operational safety. This is a requirement that covers geodetic, periodic control measurements in order to determine horizontal and vertical displacements. The paper is focused on the analysis of vertical displacements. Geodetic measurements and their interpretation allow to reduce the risk of possible structural catastrophes. The major research topic of the majority of available papers is displacement determination of individual controlled points, in a situation where there are identified as fixed reference points. There are cases making identification of such points difficult or impossible to use in displacement analysis. This paper addresses a rare case of determining vertical displacements in unstable reference systems. Due to the fact that most of the existing and known literature methods do not always bring satisfactory results, the paper propose a new method of vertical displacement determination in the absence of reference points in the local coordinate system. Practical considerations on simulated data show that the presented method performs the task correctly.

When it comes to research into changes which took place in Poland in the 10th and the first half of the 11th century and the emergence of the Piast dynasty’s state, the presence of an ethnically foreign population, its conditioning and effects have not been fully recognised. The few historiographical sources do not devote much attention to the arrival of foreign tribes; the single mentions typically pertain to the representatives of the elites, especially dynasties. Attempts have been made to analyse the phenomena by means of toponomastics and archaeology. Due to their ambiguity and late source confirmations, the results of toponomastic surveys do not allow to resolve the issue of migrations or displacement from the 10–11th centuries independently. However, the archaeological research carried out to date has revealed (beside a number of single historical objects related to the culture of Poland’s southern neighbours) grave fields and strongholds which could be potentially related to the representatives of foreign ethnic groups. The Poznań-Sołacz grave field (2nd half of the 10th century) and the Morawy grave field in Kuyavia (2nd half of the 11th century or possibly earlier) are related to a population from (Great) Moravia. Presence of a Hungarian population is traditionally attributed to the “old Hungarian” grave field in Przemyśl-Zasanie (dating back from the late 9th to the first quarter of the 11th century). On the other hand, the stronghold and the grave field in Niemcza in Silesia (dated back to the 970s and 980s) are connected with a Czech population. Unconfirmed grave fields and a handful of artefacts of Great Moravian origin are typical remains of strongholds in Gilów in Silesia and Czerchów near Łęczyca where presence of foreign warriors has not been ruled out. A question remains to what extent the material determinants of a foreign culture indicate presence of representatives of different ethnic groups and to what extent they are imports or copies. Undoubtedly, in a discussion of a foreign population genetic research may prove helpful, especially in grave fields associated with foreign populations. However, in order to analyse the issue in a comprehensive way, an interdisciplinary approach is required i.e. a combination of the methods of historical, archaeological and genetic research.

Oil can be produced from reservoirs by use of primary methods that use natural reservoir drive, secondary methods, involving a physical displacement of oil and tertiary (enhanced), in which additional types of energy support oil recovery. About 25-35% of original oil in place for light and medium oil and about 10% heavy oil could be extracted by primary and secondary methods. Injection of CO2 into the oil fields (CO2-EOR) is one of the tertiary oil recovery method. Carbon dioxide is used for increasing oil extraction due to the fact that: to maintain reservoir pressure, reduces the oil viscosity and facilitates its movement in the reservoir, reduces density and increase the volume of oil, interacts with rocks. Depending on the oil composition and the reservoir pressure and temperature injected carbon dioxide can displace oil from the reservoir miscible or immiscible. Additional 10-20% of the oil extraction over primary and secondary methods recovery can be obtained under the miscibility conditions, in immiscibility condition additional oil production is lower. EOR method selection depends on many geological, reservoir and economic parameters. These include: density, viscosity and composition of the oil, minimum miscibility pressure, the recovery factor and vertical and horizontal reservoir variability. Using the above criteria appropriate EOR method for given oil field can be selected. The five parameters: the reservoir depth, the oil density, pressure and temperature of the reservoir is used for the selection of oil fields suitable for miscible oil displacement.

As it is found in the related published literatures, the transfer function (TF) evaluation method is the most feasible method for detection of winding mechanical faults in transformers. Therefore, investigation of an accurate method for evaluation of the TFs is very important. This paper presents three new indices to compare the transformer TFs and consequently to detect the winding mechanical faults. These indices are based on estimated rational functions. To develop the method, the necessary measurements are carried out on a 1.3 MVA transformer winding, under intact condition, as well as different fault conditions (axial displacement of winding). The obtained results demonstrate the high potential of proposed method in comparison with two other well-known indices. Additionally, two important methods for describing TFs by rational functions are studied and compared in this paper.

The agglomeration of particles is a process that modifies the physical properties of a product originally manufactured as a powder. During milk powder agglomeration of fluidized bed, resulting agglomerates are sufficiently porous to improve the solubility of the final product but, at the same time, their rigidity decreases and agglomerates can be destroyed during packing. The porosity and rigidity properties depend on both the volume and shape characteristics of the agglomerates. This paper presents a three-dimensional reconstruction technique based on a laser displacement sensor (LDS) applied to characterize milk agglomerates. This technique allows three-dimensional scanning to estimate particle volume and extract shape parameters such as: sphericity, elongation and flatness ratio, shape factor and aspect ratio. This technique was implemented using a mechatronic device with two degrees of freedom. The device is composed of an angular positioning system to rotate the agglomerate and a linear positioning system to displace the LDS. Experimental result allows agglomerates classification according to shape parameters

This work presents the studies on the electrochemical process of thin palladium layers formation onto electrodeposited cobalt coatings. The suggested methodology consists of the preparation of thick and smooth cobalt substrate via galvanostatic electrodeposition. Cobalt coatings were prepared under different cathodic current density conditions from acidic bath containing cobalt sulphate and addition of boric acid. Obtained cobalt layers were analyzed by x-ray diffraction to determine their phase composition. Freshly prepared cobalt coatings were modificated by the galvanic displacement method in PdCl2 solution, to obtain smooth and compact Pd layer. The comparison of electrocatalytic properties of Co coatings with Co/Pd ones enabled to determine the influence of Palladium presence in cathodic deposits on the hydrogen evolution process.

The paper presents design and experimental verification of platform mechanism with cost-effective wire-based sensors for measuring of spatial displacement or pose of some moving object. This task, also known as spatial tracking, has a very wide application. The proposed mechanism, guided by the moving object, has a parallel structure with two platforms and at least six wire-based sensors for measuring distances between the platform points. Changes of the platform pose cause corresponding changes of the sensors' wire lengths. Forward position problem of an equivalent mechanism model with 6 degrees of freedom is described together with analyses of work space limitations and error propagation in a measurement system. A specific application is illustrated for tracking of a wheel knuckle of 5-link suspension mechanism used in passenger cars. The developed device has the following advantages: it can be installed in a wheel cavity; enables dynamic measurements on the road; is cost-effective. Performance of the latest prototype of the wire-based tracker was verified on the basis of measurements on a test rig, where two other measuring devices were used for comparison purposes.

A novel type of an axial, piston-driven high pressure hydraulic pump with variable capacity marks a significant improvement in the area of the hydraulic machinery design. Total discharge from hydrostatic forces eliminates a need for a servomechanism, thus simplifying operation, reducing weight and introducing the possibility of the pump displacement control by computer. PWK-type pumps, invented in the Gdansk University of Technology, offer high efficiency for pressure levels up to 55 MPa, ability to work self sucking even at high speed. However, the heart of the new invention, the commutation unit, creates harmful pressure peaks. Those peaks can be mitigated by the introduction of a compensation chamber with elastic walls. Owing to the dynamic character of events taking place in the pump, a need for computer simulation arouse in order to understand phenomena leading to the occurrence of pressure peaks and choose compensation chamber parameters accordingly. A CFD package alone would not be sufficient to reliably represent the interaction between the compensation chamber wall and the working fluid. This paper presents Fluid Structure Interaction approach comparing 3 different models: 2 simplified models of the pump and a full pump model.

This study presents a possibility of detecting wear of a valve plate in multi-piston axial pump based on time-frequency analysis of measured signals. Short-time Fourier transform STFT and the generalized Wigner-Ville algorithm WVD were used for this purpose. The tests were carried out on a multi-piston axial pump with swinging plate, in which the worn valve plates were mounted. Valve plate wear was related with the formation of flow micro-channels between the pump suction hole and its pumping hole on the plate transition zone surface. The developed channels initiate flow of the operational fluid, the results of which is lack of leak-tightness between suction and pumping zones, associated with a decrease in operational pressure and drop in general efficiency.

The effect of hydrogen on short-term strength, low-cycle durability and planestress fracture toughness of 10Cr15Ni27 steel, 04Cr16Ni56 and 05Cr19Ni55 alloys at pressure up to 35 MPa and temperature 293. . . 773 K was investigated. The modes of hydrogen action for which the elongation δ, reduction of area ψ, low-cycle durability N and crack resistance parameters K_c of alloys are minimal were established: hydrogen pressure above 10 MPa (non-hydrogenated specimens of 04Cr16Ni56 alloy) and above 15 MPa (hydrogenated specimens of 10Cr15Ni27 steel and 05Cr19Ni55 alloy, hydrogen concentration 15 and 19 wppm, respectively).

In the 20th century toponymy of the Kłodzko Land underwent serious changes, which with no doubt can be called a revolution. After 1945 and the displacement of the German population all the pre-war names were substituted with Polish ones, which, unfortunately, only rarely were connected with the former tradition, in some cases as old as the middle ages. Most of new names were introduced by a special commission whose main aim was to mark that the new areas gained by Poland after the World War II (the so called Regained Territories) were successfully taken into possession. However, many places and objects (some mountain tops, rock formations, springs, parts of villages) did not receive a name. In the next decades, new local communities started to accustom the mountainous landscape and independently gave names to various nameless (in Polish) places. Unfortunately, due to the depopulation of rural areas in the Kłodzko Land and other formal reasons, the process was quite slow. The main aim of the paper is not only to analyse those changes, but also to compare the numbers of names in chosen moments of the 20th century. For this purpose three types of maps in 1 : 25 000 scale were used: pre-war (German) “Meßtischblatt”, a Polish topographic map representing the situation at the beginning of the 1970s and, finally, the “Army topographic map” from the end of the 20th century. On the first map 531 geographical names were marked, on the second — only 225, and on the third — 277, which is still approximately half of the number before 1945.