The Bulletin of the Polish Academy of Sciences: Technical Sciences (Bull.Pol. Ac.: Tech.) is published bimonthly by the Division IV Engineering Sciences of the Polish Academy of Sciences, since the beginning of the existence of the PAS in 1952. The journal is peer‐reviewed and is published both in printed and electronic form. It is established for the publication of original high quality papers from multidisciplinary Engineering sciences with the following topics preferred: Artificial and Computational Intelligence, Biomedical Engineering and Biotechnology, Civil Engineering, Control, Informatics and Robotics, Electronics, Telecommunication and Optoelectronics, Mechanical and Aeronautical Engineering, Thermodynamics, Material Science and Nanotechnology, Power Systems and Power Electronics.

Journal Metrics: JCR Impact Factor 2018: 1.361, 5 Year Impact Factor: 1.323, SCImago Journal Rank (SJR) 2017: 0.319, Source Normalized Impact per Paper (SNIP) 2017: 1.005, CiteScore 2017: 1.27, The Polish Ministry of Science and Higher Education 2017: 25 points.

Abbreviations/Acronym: Journal citation: Bull. Pol. Ac.: Tech., ISO: Bull. Pol. Acad. Sci.-Tech. Sci., JCR Abbrev: B POL ACAD SCI-TECH Acronym in the Editorial System: BPASTS.

In the paper an application of evolutionary algorithm to design and optimization of combinational digital circuits with respect to transistor count is presented. Multiple layer chromosomes increasing the algorithm efficiency are introduced. Four combinational circuits with truth tables chosen from literature are designed using proposed method. Obtained results are in many cases better than those obtained using other methods.

In the paper an application of differential evolution algorithm to design digital filters with non-standard amplitude characteristics is presented. Three filters with characteristics: linearly growing, linearly falling, and non-linearly growing are designed with the use of the proposed method. The digital filters obtained using this method are stable, and their amplitude characteristics fulfill all design assumptions.

In the paper, the method of a numerical simulation concerning diagonal crack propagation in con-crete beams was presented. Two beams reinforced longitudinally but without shear reinforcement were considered during the Finite Element Method analysis. In particular, a nonlinear method was used to simulate the crack evaluation in the beams. The analysis was performed using the commercial program ANSYS. In the numerical simulation, the limit surface for concrete described by Willam and Warnke was applied to model the failure of concrete. To solve the FEM-system of equations, the Newton-Raphson method was used. As the results of FEM calculations, the trajectories of total stains and numerical images of smeared cracks were obtained for two analyzed beams: the slender beam S5 of leff = 1.8 m and the short beam S3k of leff = 1.1 m. The applied method allowed to generate both flexural vertical cracks and diagonal cracks in the shear regions. Some differences in the evaluation of crack patterns in the beams were observed. The greater number of flexural vertical cracks which penetrated deeper in the beam S5 caused the lower stiffness and the greater deformation in the beam S5 compared to the short beam S3k. Numerical results were compared with the experimental data from the early tests performed by Słowik [3]. The numerical simulation yielded very similar results as the experiments and it confirmed that the character of failure process altered according to the effective length of the member. The proposed numerical procedure was successfully verified and it can be suitable for numerical analyses of diagonal crack propagation in concrete beams.

“Soon we will be able to fit the contents of the Encyclopedia Britannica on a head of a pin,” the famous physicist Richard Feynman argued back in the 1960s. Perhaps even he would be amazed at the possibilities now offered by carbon nanotubes, several hundred thousand times tinier than a pin. Their amazing properties have been exploited in an integrated circuit developed at the Karlsruhe Institut für Technologie.

The main aim of this study was to examine the compression-induced state of stress arising in castings of the guide grates during operation

in pusher-type furnaces for heat treatment. The effect of grate compression is caused by its forced movement in the furnace. The

introduction of flexible segments to the grate structure changes in a significant way the stress distribution, mainly by decreasing its value,

and consequently considerably extends the lifetime of the grates. The stress distribution was examined in the grates with flexible segments

arranged crosswise (normal to the direction of the grate compression) and lengthwise (following the direction of force). A regression

equation was derived to describe the relationship between the stress level in a row of ribs in the grate and the number of flexible segments

of a lengthwise orientation placed in this row. It was found that, regardless of the distribution of the flexible segments in a row, the stress

values were similar in all the ribs included in this row, and in a given row of the ribs/flexible segments a similar state of stress prevailed,

irrespective of the position of this row in the whole structure of the grate and of the number of the ribs/flexible segments introduced

therein. Parts of the grate responsible for the stress transfer were indicated and also parts which play the role of an element bonding the

structure.

Various examples of the design of cast elements of the equipment used in furnaces for the heat treatment of machine parts are given.

Shortcomings in their performance are indicated. Reasons for required stability of equipment are briefly discussed. Elements of equipment

illustrate the possibilities of using a charge-carrying pallet with dimensions of 900×600×45 mm as a basis for multi-component

technological equipment. Introducing additional elements, such as metal baskets, intermediate pallets or crossbars to the main pallet, it

becomes possible to create different configurations of this equipment. The technological equipment presented and discussed here is offered

to different plants which heat-treat a wide variety of produced parts. It was found that the reliability and durability of new designed

equipment can be checked only during practical use. For large plants dealing with the heat treatment of bulk quantities of parts

homogeneous or similar in shape is recommended to use the dedicated tooling.

Laboratory and field experiments have been conducted to study mobility of chromium and lead in

floodplain sediments. The main goal of the research was to verify a hypothesis whether changes of chromium

and lead concentration could be used to estimate the relative age of floodplain deposits. The basis for undertaking such research was the presence of weaving industry centers in the Obra River valley between the 16th and

the 19th century and using Cr and Pb compounds in paint recipes. The Cr and Pb contents were also analyzed in

three vertical profiles unaffected by the field experiments. The age of organic sediments in each of the profiles

was determined using the radiocarbon analysis. The results of the laboratory experiments have shown that the

highest contents of the elements were noted in the surface layer of the sediments placed in the column. However,

the contents decreased during the last phase of the experiments and both vertical and horizontal migration of

both elements was observed. A more intensive mobility was observed in the field test. Its cause could be the

changes of the groundwater level, floodplain inundation and pH conditions in alluvial deposits. Such processes

may have influenced migration of the compounds originating from the weaving industry production; Cr and Pb

contents detected in the profiles unaffected by the field experiment were too small to be used for relative dating of alluvial deposits. Moreover, the alluvial deposits with increased contents of the studied elements may be

older than the period of the weaving industry development. Cr and Pb mobility was especially intensive in the

profiles situated within the near bed zone of the floodplain due to regular inundation, and the activity of erosion

and accumulation processes entraining the studied elements back to transport in the river bed.

The lifetime of guide grates in pusher furnaces for heat treatment could be increased by raising the flexibility of their structure through, for

example, the replacement of straight ribs, parallel to the direction of grate movement, with more flexible segments. The deformability of

grates with flexible segments arranged in two orientations, i.e. crosswise (perpendicular to the direction of compression) and lengthwise

(parallel to the direction of compression), was examined. The compression process was simulated using SolidWorks Simulation program.

Relevant regression equations were also derived describing the dependence of force inducing the grate deformation by 0.25 mm ‒ modulus

of grate elasticity ‒ on the number of flexible segments in established orientations. These calculations were made in Statistica and Scilab

programs. It has been demonstrated that, with the same number of segments, the crosswise orientation of flexible segments increases the

grate structure flexibility in a more efficient way than the lengthwise orientation. It has also been proved that a crucial effect on the grate

flexibility has only the quantity and orientation of segments (crosswise / lengthwise), while the exact position of segments changes the

grate flexibility by less than 1%.

Research concerning temporal variations of suspended sediment concentration during period of high water stages was done in the lower course of the Obra River near Międzyrzecz (Western Poland). The analysis regarding dependence of mean suspended sediment concentration and discharge allowed to determine the way of suspended sediment supply to the river bed during high water stages. It was supposed that exposures of glacial and fluvioglacial sediments in high concave banks could be an important factor influencing the amount of delivery of suspended material. Besides, normal hysteretic loops (oriented clockwise) were observed in cross-sections 4 and 5. That fact would suggest that transported material originates form the Obra River bed or its vicinity. The process of sediment accretion was observed on a fragment of drowned floodplain during high water stages. Collection of samples of freshly deposited sediment and grain size analysis allowed to illustrate the mechanism of forming floodplain sediments. It also was possible to draw near conditions of forming such sediments in the past.

Cauchy paved the way for constructing models in concrete technology, and elsewhere. He determined the (nonflat) surface area in 3D by measuring random total projections. Analogously, he determined the length of a curved line in 2D by way of measuring the total projections. The paper will present the mathematical expressions, because in many branches of concrete technology, modelling is found based on such Cauchy concepts. These branches – fractography in compression, tension or shear, fibre reinforcement and permeability estimation – will briefly be mentioned to demonstrate this. It has been found that, for the discussed fields of engineering relevance, major model parameters for cementitious materials are similar to those developed by Cauchy in the 19th century. In the paper some previous investigations concerning fractography, fibre reinforcement and fracture roughness will be summarized but basically a new development on porosimetry will be presented. Particularly a new achievement of successful implementation of the methodology (also based on Cauchy) for optimizing permeability estimation will be discussed.

Research concerning chemical constitution of alluvial sediments was done in the lower course of the Obra River (Western Poland). The fragment of vertical profile, which consisted of various alluvial sediments (fine sands, peats and sandy silts) was chosen lor detailed analysis. Main research problem was to determine if lithology and chemical constitution or alluvial deposits arc interconnected in a distinct way within studied section of' the Obra river valley, and if changes of chemical clements concentration could be used to i I lustratc depositional processes which take place in river bed and floodplain. Concentrations ofFe, Mn, Cu, Zn, Ca, Mg and K were determined in collected sediment samples. Investigated changes of chemical clements concentration show that there is a distinct border between the organic sediments, which mark the place of former functioning of the Obra river bed, and sandy silts, which were deposited within floodplain during floods. Besides, dependence between lithologic variability of alluvial sediments and their chemical constitution was observed. However, this dependence is not clear in some cases. The authors concluded that it is necessary to use statistic analyses to define connection between lithology and chemical constitution or alluvial deposits (distinguishing geochemical groups of alluvial sediments).

Research concerning changes or chosen chemical elements concentration in alluvial sediments was conducted in the lower course or the Obra river valley. The analyses of Fe, Mn, Cu, Zn, Ca, Mg and K concentration were done in a fragment or vertical profile, which was characterized by variable lithology. On the basis of statistical analysis (cluster analysis) an attempt was made to distinguish geochemical groups of alluvial sediments of the Obra river valley. Six geochemical groups, which represent reductive conditions within peat deposits, the environment ofllood sediments (inserts of fine sands within peats and sandy silts in the top of the profile) and the environment or river bed sediments (fine sands in the bottom part ofthe profile), were singled out. Results of the study show that it is possible to distinguish the above mentioned depositional environments on the basis of variations of sediments' chemical constitution.

The subject of this paper is a new procedure applied for more precise determination of material fatigue characteristics. The proposed approach is based on a special definition of the strain energy density parameter used for material fatigue property descriptions and, in the consequence, on the new algorithm of the fatigue machine control in the feedback loop. On the basis of fatigue tests under uniaxial tension-compression with the strain energy density parameter control it was proved that the fatigue characteristics in energy approach (Wa - N1) determined directly from the tests and indirectly from the Manson-Coffin relation (E,, - Nj) with the strain control for material showing cyclic stability are similar. However, for material cyclic hardening these characteristics differ significantly in high cycle fatigue regime.

The subject matter of the research pertains to the improvement of rheological properties of petroleum bitumens by their modification with SBS (styrene-butadiene-styrene) copolymer. The authors have determined selected rheological properties characterising the durability of modified bitumens used in road pavements. The bitumens were modified in laboratory conditions with modified bitumen concentrate of a known SBS copolymer content of 9%. The result was a binder containing the known percentage of the SBS copolymer of 3%, 4.5% and 6%. Rheological properties of the tested bitumens were determined by the use of a DSR dynamic shear rheometer (in a wide temperature range from 40°C to 100°C) and a ductilometer at 5°C. DSR was used for performing MSCR test to determine the resistance of the asphalt mixture with the SBS-modified binder to permanent deformations in the high temperature range (from 40°C to 82°C). The comparison of the values of the dynamic shear modulus |G*| of all the bitumens tested shows that with a growing content of the SBS copolymer in the tested binder the value of |G*| increases, which may indicate greater resistance to permanent deformation of the asphalt pavement. The MSCR test has shown that the increased use of the SBS copolymer addition in the bitumen translates to decreasing values of the non-recoverable creep compliance J_nr. The SBS copolymer accelerates stress relaxation in the bitumen sample, thus increasing pavement resistance to low-temperature cracks. Furthermore, modification reduces the negative impact of ageing on the properties of the binder, manifested by its stiffening and slowdown of relaxation.

Packaging steels are thin gauge flat carbon steels coated with tin or chrome on both sides. They are very important raw materials for the production of steel packaging, which allow food to be stored safely and with an extended shelf life. The publication focuses on the production process of ETP and ECCS steel, as well as the problem of corrosion of steel packaging.

The topic of legislative changes that require the elimination of chromium (VI) compounds from the steel passivation process was also discussed. The packaging steel industry is currently facing the need to develop a new passivation technology. Leading packaging steel manufacturers in cooperation with varnish and paint suppliers have developed chromium (VI) free technologies by implementing chromium (III) compounds and titanium oxide technology.

Authors focus also on new trends and potential development directions for the packaging steel industry.

The paper presents the results of research concerning the assessment of dynamic resistance of existing industrial hall structures located in areas with different seismic activity. The basis for analyses was a three-nave industrial hall with a steel structure. Numerical calculations were performed using the finite element method (FEM), using the response spectrum method in dynamic analysis. The calculations were carried out in variants, using standard accelerated response spectra according to Eurocode 8 and those determined for the Upper Silesian Coal Basin (USCB) and Legnica-Glogow Copper District (LGCD) area. Using the author's procedure for the assessment of the dynamic resistance, for each of the extortion analysed, the structure's response to the dynamic excitation was compared with the effects of load combinations adopted at the design stage, thus establishing the limit values of the design horizontal ground acceleration a max/g,h understood as the structure's resistance to tremors. This allowed to assess the impact of seismic activity from a specific area on the dynamic resistance of the subjected object. The article also discusses the way of interpretation and the scope of application of the obtained results and proposed procedure.