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Number of results: 222
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Abstract

The attempt was made to describe the dynamics of water masses in the southern part of the Drake Passage and the Bransfield Strait in the time period from December 1983 to January 1984. The dynamic topography at the surface (referred to 500 dbar surface) allowed to define the eastward flow of water in the Bransfield Strait and to observe, in the same region, the presence of a rather weak counter-current of the Weddell Sea origin. In the Drake Passage, a general north-eastern direction of water flow of the Bellingshausen Sea was found. In the Bransfield Strait, as well as in the Drake Passage, the relative velocities of geostrophic flow were low: 0.22 and 0.06 m s-1 respectively. The analysis of Rossby and eddy numbers and Rossby radius made it possible to regionalize the dynamic phenomena but could not be fully used for their classification.
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Abstract

During the planning and controlling of the construction process, most attention is focu sed on risk analysis, especially in the context of final costs and deadlines of the investment. In this analysis, the primary and most significant concern is the proper identification and quantification of events, which on a certain level of probability may affect the development process. This paper presents the result of a risk analysis for a particular building object, made after completion of the investment and accepting it for use. Knowledge of the planned values and the actual investment process allowed for the identification of the events and their effects that in this case have significantly disrupted the investment process. The limited total cost of the investment project in question had a considerable impact on the progress of the project execution. Despite three transitions of administrative procedures, the opening date of the shopping centre was delayed by only three weeks.
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Abstract

The problems related to construction production are multi-faceted and complex. This has promoted the search for different methods/approaches for analizing the data which supports the decision-making process in the construction industry. In the article the authors focus their attention on well-known methods and tools, and on some new approaches to solving decision-making problems. The aim of the article is to analyze the methods used to analyse data in a construction company, convey their advantages and disadvantages, and specify the degree of efficiency in the discussed area.
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Abstract

In this paper is discussed the effect of the inoculant mischmetal addition on the microstructure of the magnesium alloy AZ91. The concentration of the inoculant was increased in the samples within the range from 0.1% up to 0.6%. The thermal process was performed with the use of Derivative and Thermal Analysis (DTA). A particular attention was paid to finding the optimal amount of the inoculant, which causes fragmentation of the microstructure. The concentration of each element was verified with use of a spark spectrometer. In addition, the microstructures of every samples were examined with the use of an optical microscope and also was performed an image analysis with a statistical analysis using the NIS–Elements program. The point of those analyses was to examine the differences in the grain diameters of phase αMg and eutectic αMg+γ(Mg17Al12) in the prepared samples as well as the average size of each type of grain by way of measuring their perimeters. This paper is the second part of the introduction into a bigger research on grain refinement of magnesium alloys, especially AZ91. Another purpose of this research is to achieve better microstructure fragmentation of magnesium alloys without the relevant changes of the chemical composition, which should improve the mechanical properties.
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Abstract

Complex analysis ofgeomorphological glacial processes in forefields of retreating glaciers in the southern Bellsund region was undertaken. Field studies and archival cartographic materials indicate continued glacial retreat, at least since the turn of the 19th and 20th centuries. Its average present rate of about 20 m/y is rather high and no moraine ridges are formed, except for the fluted moraines. Forefields of large glaciers are characterized by typical relief and sediments of frontal deglaciation only. Intensity and extent of glacial forefield remodelling depends mainly on activity ablation waters. At present glaciofluvial erosion predominates.
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Abstract

The article raised issues related to the design and execution of low-energy objects in Polish conditions. Based on the designed single-family house, adapted to the requirements of the National Fund for Environmental Protection and Water Management ("NF40" standard), the tools to assist investment decisions by investors were shown. An economic analysis and a multi-criteria analysis were performed using AHP method which had provided an answer to the question whether it is worthwhile to bear higher investment costs in order to adjust to the standards of energy-efficient buildings that fulfil a minimal energy consumption's requirements contained in Polish law. In addition, the variant of object that had optimal characteristics due to the different preferences of investors was indicated. This paper includes analysis and observations on the attempts to unify that part of the building sector, which so far is considered to be personalized, and objects in accordance with the corresponding idea are designed as "custom-made".
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Abstract

A mine cannot function without monitoring systems: environmental, basic mining machinery and equipment. The exploitation of ore in the mine depends heavily on properly functioning machines and mining equipment, and acceptable for the miner technical environmental conditions occurring in underground excavations. The monitoring systems of the technical environment in underground mines are primarily telemetry and gasometry systems. The first part of the article shows the typical structure of gasometry systems operating in the Polish underground mines. The existing provisions include the so-called security systems of the mining plant. The article presents a quantitative summary of the telephone exchange types and count of main telecommunication lines operating in these systems. Monitoring systems of machines and mining equipment are an essential element of the effec-tive management of the mine, because they affect the safe operation and increase time of effi-ciency equipment. The second part of the article shows selected monitoring systems of mining machinery and equipment currently used in the dispatcher rooms of mines. Attention was paid to the monitoring systems, which are only software tools as well as those in which additionally use dedicated IT solutions for these systems, hardware and measuring tools. The table shows the types of monitoring systems and technological configurations used in underground mines, preferred for them.
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Abstract

The complexity of the phenomena associated with the course of the cognitive processes that determine an efficient learning, excludes the possibility of collecting knowledge in other ways than neuronal-information. It excludes also possibilities of interpreting it, in other ways than with use of respectively formalized cognitive models. The presented paper is a kind of summary of the latest achievements in this field.
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Abstract

In recent years, the Budryk Coal Mine (KWK Budryk) reached the mining depth of 1300 m, where there is about 160 million tons of coal, including 120 million tons of coking coal (type 35). The task of the Coal Processing Plant complex modernization was undertaken. The article presents the modernization of coal screening, classification and dewatering systems at the KWK Budryk Processing Plant and the implementation of screening of PROGRESS ECO sp. z o.o. SK. The modernization project defined the following technical requirements for all screens in the KWK Budryk Coal Processing Plant extension project: - Vibrating screens with a linear type drive with a drive unit placed on the drive beam of the trommel screen in the form of vibration generators; - Screen drives equipped with a starting-braking device; - The use of main screen drive bearings with a nominal service life of at least 40,000 man-hours; - All work surfaces made of materials with a strength of up to 80 mm grain and abrasion resistance; side strips and sieves fixed in a way ensuring trouble-free operation, and at the same time quick and easy replacement; - Sheets made of stainless steel; - Side walls, beams and other elements attached to them connected with screws using a system protecting against corrosion and elements separation; - The use of a work parameters monitoring and visualization system, i.e. - pitch of the riddle, - bearing operating temperatures and the condition of their wear. Three types of screens were provided: - PWP1-1Z-2,8x6,0 screeners that alternatively perform sieving or desliming processes, - PWP1-2.4x6.0 screening machines performing desliming processes, - PWP1-2.0x6.0 screens performing the classification process.
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Abstract

Accurate demagnetization modelling is mandatory for a reliable design of rare-earth permanent magnet applications, such as e.g. synchronous machines. The magnetization of rare-earth permanent magnets requires high magnetizing fields. For technical reasons, it is not always possible to completely and homogeneously achieve the required field strength during a pulse magnetization, due to stray fields or eddy currents. Not sufficiently magnetized magnets lose remanence as well as coercivity and the demagnetization characteristic becomes strongly nonlinear. It is state of the art to treat demagnetization curves as linear. This paper presents an approach to model the nonlinear demagnetization in dependence on the magnetization field strength. Measurements of magnetization dependent demagnetization characteristics of rare-earth permanent magnets are compared to an analytical model description. The physical meaning of the model parameters and the influence on them by incomplete magnetization are discussed for different rare-earth permanent magnet materials. Basically, the analytic function is able to map the occurring magnetization dependent demagnetization behavior. However, if the magnetization is incomplete, the model parameters have a strong nonlinear behavior and can only be partially attributed to physical effects. As a benefit the model can represent nonlinear demagnetization using a few parameters only. The original analytical model is from literature but has been adapted for the incomplete magnetization. The discussed effect is not sufficiently accurate modelled in literature. The sparse data in literature has been supplemented with additional pulsed-field magnetometer measurements.
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Abstract

Many wire products (e.g. nets) are made from galvanized material. The hot dip galvanizing process gives the possibility of applying in a respectively thick coat of zinc (also depending on the time of staying wires in the bath) which provides the protection of the product against corrosion. In the available literature there were no research concerned with the influence of hot dip galvanizing process on the mechanical properties TRIP structure steel wires. Therefore, an experiment was carried out in laboratory conditions allowing the determination of the influence of hot dip galvanizing process parameters on the mechanical properties (tensile strength UST and yield strength YS) of TRIP steel wires as well as on the amount of retained austenite in their structure. It has been stated that the hot galvanizing process of TRIP steel wires influences, proportionally to the time of staying wires in zinc bath, on their plastic properties (the increase in yield strength YS) as well as the decrease in the amount of retained austenite in their structure. Such a phenomenon can be caused by stresses responsible for rapid heating of the wire put in the zinc bath in temperature of 450°C and by the strengthening of the materials resulting from the transformation of retained austenite.
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Abstract

Control of the technological processes of coal enrichment takes place in the presence of wide disturbances. Thus, one of the basic tasks of the coal enrichment process control systems is the stabilization of coal quality parameters at a preset level. An important problem is the choice of the controller which is robust for a variety of disturbances. The tuning of the controller parameters is no less important in the control process . Many methods of tuning the controller use the dynamic characteristics of the controlled process (dynamic model of the controlled object). Based on many studies it was found that the dynamics of many processes of coal enrichment can be represented by a dynamic model with properties of the inertial element with a time delay. The identification of object parameters (including the time constant) in industrial conditions is usually performed during normal operation (with the influence of disturbances) from this reason, determined parameters of the dynamic model may differ from the parameters of the actual process. The control system with controller parameters tuned on the basis of such a model may not satisfy the assumed control quality requirements. In the paper, the analysis of the influence of changes in object model parameters in the course of the controlled value has been carried out. Research on the controller settings calculated according to parameters T and τ were carried out on objects with other parameter values. In the studies, a sensitivity analysis method was used. The sensitivity analysis for the three methods of tuning the PI controller for the coal enrichment processes control systems characterized by dynamic properties of the inertial element with time delay has been presented. Considerations are performed at various parameters of the object on the basis of the response of the control system for a constant value of set point. The assessment of considered tuning methods based on selected indices of control quality have been implemented.
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Abstract

This article proposes a model describing the nature of associative processes as diagnostic cues for formulating attitudes and judgments. The assumption of the model is that attitudes, judgments and behaviours are based on how people selectively activate, interpret and integrate previously associated signals (selectively limiting the excess of information from both the senses and from our immediate environment). The model specifies which factors hinder or facilitate the formulation of associations between diagnostic signals and how it translates into attitudes, judgments and behaviours. To test the predictions derived from this model, we first showed that linguistic cues of diminutives can indicate physical properties – they were associated with the belief that the described objects were smaller but also worse or less valuable. The second line of research dealt with embodied moral judgments – we demonstrated that the usage of a hand over heart gesture led to more honest behaviour, an increase in judgments of honesty but also reduced tendency to lie for one's own profit. Our findings also suggest that using “standing at attention” body manipulation increased participants' submissiveness to the experimenter and their obedience to norms. This pattern of results suggests that the described model integrates perspectives of embodied cognition and social cognition, documenting the cognitive mechanism needed to formulate and adjust attitudes and judgments.
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Abstract

The main purpose of the presented research is to investigate the partial discharge (PD) phenomenon variability under long-term AC voltage with particular consideration of the selected physical quantities changes while measured and registered by the acoustic emission method (AE). During the research a PD model source generating surface discharges is immersed in the brand new insulation mineral oil. Acoustic signals generated by the continuously occurred PDs within 168 hours are registered. Several qualitative and quantitative indicators are assigned to describe the PD variability in time. Furthermore, some longterm characteristics of the applied PD model source in mineral oil, are also presented according to acoustic signals emitted by the PD. Finally, various statistical tools are applied for the results analysis and presentation. Despite there are numerous contemporary research papers dealing with long-term PD analysis, such complementary and multiparametric approach has not been presented so far, regarding the presented research. According to the presented research from among all assigned indicators there are discriminated descriptors that could depend on PD long-term duration. On the grounds of the regression models analysis there are discovered trends that potentially allow to apply the results for modeling of the PD variability in time using the acoustic emission method. Subsequently such an approach may potentially support the development and extend the abilities of the diagnostic tools and maintenance policy in electrical power industry.
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Abstract

In this paper methods and their examination results for automatic segmentation and parameterization of vessels based on spectral domain optical coherence tomography (SD-OCT) of the retina are presented. We present three strategies for morphologic image processing of a fundus image reconstructed from OCT scans. A specificity of initial image processing for fundus reconstruction is analysed. Then, the parameterization step is performed based on the vessels segmented with the proposed algorithm. The influence of various methods on the vessel segmentation and fully automatic vessel measurement is analysed. Experiments were carried out with a set of 3D OCT scans obtained from 24 eyes (12 healthy volunteers) with the use of an Avanti RTvue OCT device. The results of automatic vessel segmentation were numerically compared with those prepared manually by the medical doctor experts.
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Abstract

The general objective of this research has been to identify the factors and conditions of migration of CaCO3 within glaciers and their marginal zones in Svalbard . Special attention has been paid to the cryochemical processes responsible for precipitation of calcium carbonate in icing (naled ice) formed near fronts of polythermal glaciers during winter. Estimates of the importance of those processes in respect of the general mineral mass transfer in the glacier system are attempted here. Field studies concerning the carbonate contents in proglacial sediments and icing fields were carried out in the Werenskioldbreen and the Elisebreen basins (S and NW Spitsbergen respectively). A functional model of CaCO3 migration in a glacier system is proposed which indicates the various paths of the mineral mass flow. Considerations on intensity of glacial processes permitted quantitative estimation of the particular components in respect to the Werenskioldbreen basin. Cryochemical processes do not appear to be of overriding importance in such migration but, clearly, they play a specific role in retaining CaCO3 in the proglacial zone on land. The crystalline forms present in the icings, which have many lattice defects, are very easily re-dissolved or removed by wind.
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Abstract

This article presented some critical remarks relating to the understanding of the panen-theism as a postmodern revelation, proposed by David Ray Griffin in his book Panentheism and Scientific Naturalism. Rethinking Evil, Morality, Religious Experience, Religious Pluralism, and the Academic Study of Religion. The main objection relates to the question that the American philosopher and theologian presents the philosophical, not theological conception of revelation. In addition he used the assumptions taken from process philosophy of A.N. Whitehead to construct this conception. The result of these assumptions is a new and original understanding of postmodernism. According to these assumptions panentheism is a conception that reflects properly the God-world relationship. Moreover, panentheism, as Griffin said, avoids mistakes of classical theism and extremes of early and late modernity. This panentheism is an integral part of naturalismppp. Griffin’s attempt to equate panentheism and revelation is based on the interaction recognized by him between God and the world. It manifests in the religious experiences and in the human drive to discover truth, which is, as Griffin said, a divinely-instilled drive. Process panentheism is the attempt to reconcile this revelation with the revelation that comes to us through the Abrahamic and other the-istic traditions. But it is difficult to accept that the revelation that comes to us from these religions, especially the revelation realized in Jesus Christ, gave rise to the recognition of the God-world relationship in terms of panentheism proposed by process theology
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Abstract

The mathematical model and numerical simulations of the solidification of a cylindrical shaped casting, which take into account the process of filling the mould cavity by liquid metal and feeding the casting through the riser during its solidification, are presented in the paper. Mutual dependence of thermal and flow phenomena were taken into account because have an essential influence on solidification process. The effect of the riser shape on the effectiveness of feeding of the solidifying casting was determined. In order to obtain the casting without shrinkage defects, an appropriate selection of riser shape was made, which is important for foundry practice. Numerical calculations of the solidification process of system consisting of the casting and the conical or cylindrical riser were carried out. The velocity fields have been obtained from the solution of momentum equations and continuity equation, while temperature fields from solving the equation of heat conductivity containing the convection term. Changes in thermo-physical parameters as a function of temperature were considered. The finite element method (FEM) was used to solve the problem.
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Abstract

In this paper, aluminium alloy of grade ADC-12 was considered as a base metal and chromium carbide (Cr3C2) particles were reinforced through friction stir process. A detailed analysis of mechanical property and metallurgical characterization studies were performed to evaluate the surface composite. Remarkable changes were observed in the developed composite due to the mechanical force produced by the stir tool with an increase in hardness. The metallurgical investigation infers that the presence of silica in ADC-12 alloys has undergone mechanical fracture and long needle structure changed to reduced size. On the other hand, at higher tool rotational speed, the uniform distribution of hard particles was confirmed through SEM micrographs. Thus the modified surface composite has produced good mechanical property with high metallurgical qualities.
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Abstract

The study presents the results of laboratory testing of the phenomenon of cracking in the process of cross rolling. A new method of determining the critical value of the damage function was developed, in which a disc-shaped sample is subjected to rotational compression in a channel. In this method the Mannesmann effect was used. The laboratory tests were conducted for C45, 50HS and R260 grade steel in the temperature range 950°C-1150°C. In order to research various methods of simulating the phenomenon of cracking in the process of cross rolling, physical modelling was also employed. The model material was commercial plasticine, cooled to the temperature 0°C-20°C. Comparing the test results for both the real and model material allowed one to determine the range of the forming temperature for the model material, in which the cracking process is similar to the case of the real material.
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Abstract

The computing performance optimization of the Short-Lag Spatial Coherence (SLSC) method applied to ultrasound data processing is presented. The method is based on the theory that signals from adjacent receivers are correlated, drawing on a simplified conclusion of the van Cittert-Zernike theorem. It has been proven that it can be successfully used in ultrasound data reconstruction with despeckling. Former works have shown that the SLSC method in its original form has two main drawbacks: time-consuming processing and low contrast in the area near the transceivers. In this study, we introduce a method that allows to overcome both of these drawbacks. The presented approach removes the dependency on distance (the “lag” parameter value) between signals used to calculate correlations. The approach has been tested by comparing results obtained with the original SLSC algorithm on data acquired from tissue phantoms. The modified method proposed here leads to constant complexity, thus execution time is independent of the lag parameter value, instead of the linear complexity. The presented approach increases computation speed over 10 times in comparison to the base SLSC algorithm for a typical lag parameter value. The approach also improves the output image quality in shallow areas and does not decrease quality in deeper areas.
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Abstract

The paper presents the results of investigations concerning the influence of gray cast iron modification on free vibration frequency of the disc casting. Three different chemical composition melts of gray cast iron were prepared in induction furnace. During gravity casting 0.05% and 0.3% mass of the Inolate modifier was added on stream of metal for changing graphite flakes in castings. Sound signal vibration of cast iron sample was registered by means on microphone for free vibration frequency measurements. Decreasing of free vibration frequency of modified cast iron in comparison with non modified castings was observed. Higher contents of modifier causes more decreasing of free vibration frequency. Cast iron with smaller contents of carbon and silicon have higher free vibration frequency in comparison with eutectic composition cast iron. Hardness of examined cast iron is lower when the more modifier is added during modification process. Free frequency is smaller with smaller Brinell hardness of disc casting. It was concluded that control of free vibration frequency of disc castings by means of chemical composition and modification process can improved comfort and safety of working parts.
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Abstract

The paper presents the results of preliminary research on the application of olivine moulding sands with hydrated sodium silicate containing 1.5 % wt. of binder to perform ecological casting cores in hot-box technology using a semi-automatic core shooter. The following parameters were used in the process of core shooting: initial shot pressure of 6 bar, shot time 3 s, the temperature of the corebox: 200, 250 and 300 °C and the core curing time: 30, 60, 90, 120 and 150 s. The matrix of the moulding mixture was olivine sand, and the binder of the sandmix was commercial, unmodified hydrated sodium silicate with molar module SiO2/Na2O of 2.5. In one shot of the automatic core-shooter were formed three longitudinal specimens (cores) with a dimensions 22.2×22.2×180 mm. The samples obtained in this way were subjected to the assessment of the influence of the shooting parameters, i.e. shooting time, temperature and curing time in core-box, using the following criteria: core box fill rate, mechanical strength to bending Rg U, apparent density, compaction degree and susceptibility to friability of sand grains after hardening. The results of trials on the use of olivine moulding sands with hydrated sodium silicate (olivine SSBS) in the process of core shooting made it possible to determine the conditions for further research on the improvement of inorganic hot-box process technology aimed at: reduction of the heating temperature and the curing time. It was found that correlation between the parameters of the shooting process and the bending strength of olivine moulding sands with sodium silicate is observed.
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Abstract

The accurate prediction of iron losses has become a prominent problem in electromagnetic machine design. The basis of all iron loss models is found in the spatial field-locus of the magnetic flux density (B) and magnetic field (H). In this paper the behavior of the measured BH-field-loci is considered in FEM simulation. For this purpose, a vector hysteresis model is parameterized based on the global measurements, which then can be used to reproduce the measurement system and obtain more detailed insights on the device and its local field distribution. The IEM has designed a rotary loss tester for electrical steel, which can apply arbitrary BH-field-loci occurring during electrical machine operation. Despite its simplicity, the proposed pragmatic analytical model for vector hysteresis provides very promising results.
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Abstract

The field of academic research on corporate sustainability management has gained significant sophistication since the economic growth has been associated with innovation. In this paper, we are to show our research project that aims to build an artificial intelligence-based neurofuzzy inference system to be able to approximate company’s innovation performance, thus the sustainability innovation potential. For this we used an empirical sample of Hungarian processing industry’s large companies and built an adaptive neuro fuzzy inference system.
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