The article presents a synthetic analysis of the crude oil market in Poland. As of today, this safety is provided mainly on the basis of native lignite and hard coal resources. However, the analysis of the hard coal market conducted by the authors indicates that the carried out mining restructuring (among others) led to an excessive reduction of mining volume and employment level in the hard coal mining sector. This led to a precedent situation when Poland became an importer of this energy carrier. In addition, the European Union’s requirements for greenhouse gas emissions must be taken into account. In connection with the above, it is necessary to search for new energy sources or technologies that enable hard coal to meet the requirements. It is possible to apply the so-called clean coal technologies that allow the greenhouse gas emissions generated during coal combustion to be reduced. As of today, they are not used on a mass scale, because the use of this type of technology involves additional financial expenses. However, taking into account that technologies have been growing faster and faster, are modernized in a shorter time, making a breakthrough discovery took hundreds of years, now it is often a few months, clean coal technologies can become the optimal solution in the near future. It is also necessary to diversify the sources of obtaining imported energy carriers. The article describes coal and crude oil in terms of their mutual substitution. The article is a continuation of research conducted by the authors. Previous publications presented considerations on analogous topics related to natural gas and renewable energy sources. The crude oil market in Poland was analyzed and forecasts for oil extraction and the demand in the world and Poland by 2023 were presented. The SARIMA model was also created. The model made it possible to obtain oil an prices forecast.
During four Polish Geodynamical Expeditions to West Antarctica between 1979 and 1991, seismic measurements were made along 21 deep refraction profiles in the Bransfield Strait and along the coastal area of Antarctic Peninsula using explosion sources. Recordings were made by 16 land stations and 8 ocean bottom seismometers. Good quality recordings were obtained up to about 250 km distance. This allowed a detailed study of the seismic wave field and crustal structure. Three-dimensional tomographic inversion was carried out using first arrivals from the complete data set including off-line recordings. As a result, we obtained a 3-D model of the P-wave velocity distribution in the study area. In the area adjacent to the Antarctic Peninsula coast, sedimentary cover of 0.2 to 3 km thickness was found, whereas in the shelf area and in the Bransfield Strait sedimentary basins with thickness from 5 to 8 km were observed. In the Bransfield Strait a high velocity body with Vp > 7.5 km/s was found at 12 km depth. The use of the off-line data allowed for determination of the horizontal extent of the body. The thickness of the crust varies from more than 35-40 km in the coastal area south of the Hero Fracture Zone to 30-35 km in the area of Bransfield Strait and South Shetland Islands and about 12 km in the Pacific Ocean NW of South Shetland Islands.
Philip Sabin points out that modern wargames not only contain substantial amounts of historical information but also arrange it into interactive models which depict historical processes in a simplified manner. Such models can be used in historical research as well, complementing the discourse through more holistic and mathematically strict accounts, and providing tools that impose some discipline on counter- factual speculation.
The objective of this work was to generate a series of equations to describe the voltinism of Lobesia botrana in the quarantine area of the main winemaking area of Argentina, Mendoza. To do this we considered an average climate scenario and extrapolated these equations to other winegrowing areas at risk of being invaded. A grid of 4 km2 was used to generate statistics on L. botrana captures and the mean temperature accumulation for the pixel. Four sets of logistic regression were constructed using the percentage of accumulated trap catches/grid/week and the degree-day accumulation above 7°C, from 1st July. By means of a habitat model, an extrapolation of the phenological model generated to other Argentine winemaking areas was evaluated. According to our results, it can be expected that 50% of male adult emergence for the first flight occurs at 248.79 ± 4 degree-days (DD), in the second flight at 860.18 ± 4.1 DD, while in the third and the fourth flights, 1671.34 ± 5.8 DD and 2335.64 ± 4.3 DD, respectively. Subsequent climatic comparison determined that climatic conditions of uncolonized areas of Cuyo Region have a similar suitability index to the quarantine area used to adjust the phenological model. The upper valley of Río Negro and Neuquén are environmentally similar. Valleys of the northwestern region of Argentina showed lower average suitability index and greater variability among SI estimated by the algorithm considered. The combination of two models for the estimation of adult emergence time and potential distribution, can provide greater certainties in decision-making and risk assessment of invasive species.
BIM (Building Information Modelling) is a tool and technology closely related to the planning, design, implementation and management of construction investments – both at the level of a building, as well as infrastructure or civil engineering. It combines advanced spatial modeling (using virtual representations of building elements) with management of information at every level, from the modelling of building’s components, through complex interactions between these elements, to the description of building processes and the behavior of users of the building. This is just a part of many possibilities, the full application depends only on the needs and skills of the system user. Construction dependencies are set at the level of the IFC (Industry Foundation Class) universal standard IFC, its syntax allows to describe not only the physical structure of the object, but also their mutual interactions. This is done in a hierarchical way, i.e. from the superior element there are subsequent, lower-level elements and interactions. So how can this tool be used in urban revitalization? The basic problem here is the excess of information related to and contained in the virtual model. In urban planning and design, most of this data is unnecessary. On the other hand, the data contained in the GIS (Geographic Information System) models, despite correlation with external databases, are insufficient. Basic location data, technical conditions of facilities and infrastructure, property dependencies are not enough to obtain a full picture of the urban space. The solution to the problem of linking these systems is CIM (City Information Modeling). It combines the description of an object derived from IFC with database support at the level of GIS systems. Such a broad approach allows for placing enough information in one virtual space for designing, modeling and analyzing urban space. The article is an attempt to demonstrate what conditions must be met by the CIM system, to extend its functionality to issues related to the revitalization of urban areas: whether and how the information contained in the spatial model can be used to determine the rules for the revitalization of space at the urban level?
The study concerns modeling and simulation of the growth of biofilms with heterogeneous structures with a discrete mathematical model based on theory of cellular automata. The article presents two-dimensional density distributions of biofilms for microbial processes: oxidation of ammonium by Nitrosomonas europaea bacteria and glucose utilization by Pseudomonas aeruginosa bacteria. The influence of limiting substrate concentration in the liquid phase on biofilm structure was determined. It has been shown that the value of death rate coefficient of microorganisms has the qualitative and quantitative influence on the density and porosity of the biofilm.
Magnetic properties of silicon iron electrical steel are determined by using standardized measurement setups and distinct excitation parameters. Characteristic values for magnetic loss and magnetization are used to select the most appropriate material for its application. This approach is not sufficient, because of the complex material behavior inside electrical machines, which can result in possible discrepancies between estimated and actual machine behavior. The materials’ anisotropy can be one of the problems why simulation and measurement are not in good accordance.With the help of a rotational single sheet tester, the magnetic material can be tested under application relevant field distribution. Thereby, additional effects of hysteresis and anisotropy can be characterized for detailed modelling and simulation.
The article discusses changes in Polish regulations concerning assessment of the climate hazard in underground mines. Currently, the main empirical index representing the heat strain, used in qualification of the workplace to one of the climate hazard levels in Poland is the equivalent climate temperature. This simple heat index allows easy and quick assessment of the climate hazard. To a major extent, simple heat indices have simplifications and are developed for a specific working environments. Currently, the best methods used in evaluation of microclimate conditions in the workplace are those based on the theory of human thermal balance, where the physiological parameters characterising heat strain are body water loss and internal core temperature of the human body. The article describes the results of research on usage of equivalent climate temperature to heat strain evaluation in underground mining excavations. For this purpose, the numerical model of heat exchange between man and his environment was used, taken from PN-EN ISO 7933:2005. The research discussed in this paper has been carried out considering working conditions and clothing insulation in use in underground mines. The analyses performed in the study allowed formulation of conclusions concerning application of the equivalent climate temperature as a criterion of assessment of climate hazards in underground mines.
In the paper, a procedure for precise and expedited design optimization of unequal power split patch couplers is proposed. Our methodology aims at identifying the coupler dimensions that correspond to the circuit operating at the requested frequency and featuring a required power split. At the same time, the design process is supposed to be computationally efficient. The proposed methodology involves two types of auxiliary models (surrogates): an inverse one, constructed from a set of reference designs optimized for particular power split values, and a forward one which represents the circuit S-parameter gradients as a function of the power split ratio. The inverse model directly yields the values of geometry parameters of the coupler for any required power split, whereas the forward model is used for a post-scaling correction of the circuit characteristics. For the sake of illustration, a 10-GHz circular sector patch coupler is considered. The power split ratio of the structure is re-designed within a wide range of ��6 dB to 0 dB. As demonstrated, precise scaling (with the power split error smaller than 0.02 dB and the operating frequency error not exceeding 0.05 GHz) can be achieved at the cost of less than three full-wave EM simulations of the coupler. Numerical results are validated experimentally.
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.
The presence of lipopolysaccharide (LPS) in blood induces an inflammatory response which leads to multiple organ dysfunction and numerous metabolic disorders. Uncontrolled, improper or late intervention may lead to tissue hypoxia, anaerobic glycolysis and a disturbance in the acid -base balance. The effects of LPS-induced toxemia on biological and immunological markers were well studied. However, parameters such as base excess, ions, and acid-base balance were not fully investigated. Therefore, the objective of this study was to examine these blood parameters collectively in LPS-induced inflammatory toxemia in rat’s model. After induction of toxemia by injecting LPS at a rate of 5 mg/kg body weight intravenously, blood was collected from the tail vein of twenty rats and immediately analyzed. After 24 hours, the animals were sacrificed and the blood was collected from the caudal vena cava. The results revealed that the levels of pH, bicarbonate, partial pressure of oxygen, oxygen saturation, Alveolar oxygen, hemoglobin, hematocrit, magnesium (Mg2+), and calcium (Ca2+) were significantly decreased. On the other side, the levels of Base excess blood, Base excess extracellular fluid, partial pressure of carbon dioxide, lactate, Ca2+/Mg2+, potassium, and chloride were significantly increased compared to those found pre toxemia induction. However, sodium level showed no significant change. In conclusion, Acute LPS-toxemia model disturbs acid-base balance, blood gases, and ions. These parameters can be used to monitor human and animal toxemic inflammatory response induced by bacterial LPS conditions to assist in the management of the diagnosed cases.
The quantitative description of an airlift bioreactor, in which aerobic biodegradation limited by carbonaceous substrate and oxygen dissolved in a liquid takes place, is presented. This process is described by the double-substrate kinetics. Mathematical models based on the assumption of plug flow and dispersion flow of liquid through the riser and the downcomer in the reactor were proposed. Calculations were performed for two representative hydrodynamic regimes of reactor operation, i.e. with the presence of gas bubbles only within the riser and for complete gas circulation. The analysis aimed at how the choice of a mathematical model of the process would enable detecting the theoretical occurrence of oxygen deficiency in the airlift reactor. It was demonstrated that the simplification of numerical calculations by assuming the “plug flow” model instead of dispersion with high Péclet numbers posed a risk of improper evaluation of the presence of oxygen deficiency zones. Conclusions related to apparatusmodelling and process design were drawn on the basis of the results obtained. The paper is a continuation of an earlier publication (Grzywacz, 2012a) where an analysis of single-substrate models of the airlift reactor was presented.
Introduction: Platelet-rich plasma (PRP) preparations can be used in bone tissue healing but there are numerous doubts among clinical orthopedists about effectiveness of this method. Materials and methods: The studies were carried out in 12 rabbits of white termond breed. In operating room we operationally generated cylindrical, unicortical defects of the diameter of 4 mm in the middle of the shafts of both femurs. The defects in the left bones were left without filling and served as controls, and 0.7 ml of the ready-to-use PRP was administered to the defects in the right bones (experimental group). We evaluated the usefulness of the diagnostic methods applied: biomechanical tests, micro-CT tests, densitometry, typical radiology, macroscopic measurements, histopathological examinations. Results: The macroscopic measurements showed a statistically significant increase in the dimension in the area of the right defect filled with PRP in relation to the control group. In experimented group, the assessment of the X-ray images showed the formation of a callus cuff around the defects. Densitometric examinations showed no statistically significant differences between defects in the experimental and control group. The analysis of the micro-CT examina- tions showed an increase in the total volume of the tissue examined (Vb) and the low density tissue fraction (Vb2) in the experimental group. The biomechanical examinations revealed signi- ficant decrease in the maximum breaking force (F max) necessary to break the bone in the experi- mental group in relation to the control group. Conclusions: Platelet-rich plasma (PRP) stimulates bone formation in the area of bone defects and may accelerate bone regeneration.
This paper presents a complex study of anhydrite interbeds influence on the cavern stability in the Mechelinki salt deposit. The impact of interbeds on the cavern shape and the stress concentrations were also considered. The stability analysis was based on the 3D numerical modelling. Numerical simulations were performed with use of the Finite Difference Method (FDM) and the FLAC3D v. 6.00 software. The numerical model in a cuboidal shape and the following dimensions: length 1400, width 1400, height 1400 m, comprised the part of the Mechelinki salt deposit. Three (K-6, K-8, K-9) caverns were projected inside this model. The mesh of the numerical model contained about 15 million tetrahedral elements. The occurrence of anhydrite interbeds within the rock salt beds had contributed to the reduction in a diameter and irregular shape of the analysed caverns. The results of the 3D numerical modelling had indicated that the contact area between the rock salt beds and the anhydrite interbeds is likely to the occurrence of displacements. Irregularities in a shape of the analysed caverns are prone to the stress concentration. However, the stability of the analysed caverns are not expected to be affected in the assumed operation conditions and time period (9.5 years).
Rock excavation is a basic technological operation during tunnelling and drilling roadways in underground mines. Tunnels and roadways in underground mines are driven into a rock mass, which in the particular case of sedimentary rocks, often have a layered structure and complicated tectonics. For this reason, rock strata often have highly differentiated mechanical properties, diverse deposition patterns and varied thicknesses in the cross sections of such headings. In the field of roadheader technology applied to drilling headings, the structure of a rock mass is highly relevant when selecting the appropriate cutting method for the heading face. Decidedly differentiated values of the parameters which describe the mechanical properties of a particular rock layer deposited in the cross section of the drilled tunnel heading will influence the value and character of the load on the cutting system, generated by the cutting process, power demand, efficiency and energy consumption of the cutting process. The article presents a mathematical modelling process for cutting a layered structure rock mass with the transverse head of a boom-type roadheader. The assumption was made that the rock mass being cut consists of a certain number of rock layers with predefined mechanical properties, a specific thickness and deposition pattern. The mathematical model created was executed through a computer programme. It was used for analysing the impact deposition patterns of rock layers with varied mechanical properties, have on the amount of cutting power consumed and load placed on a roadheader cutting system. The article presents an example of the results attained from computer simulations. They indicate that variations in the properties of the rock cut – as cutting heads are moving along the surface of the heading face – may have, apart from multiple other factors, a significant impact on the value of the power consumed by the cutting process.
This article considers designing of a renewable electrical power generation system for self-contained homes away from conventional grids. A model based on a technique for the analysis and evaluation of two solar and wind energy sources, electrochemical storage and charging of a housing area is introduced into a simulation and calculation program that aims to decide, based on the optimized results, on electrical energy production system coupled or separated from the two sources mentioned above that must be able to ensure a continuous energy balance at any time of the day. Such system is the most cost-effective among the systems found. The wind system adopted in the study is of the low starting speed that meets the criteria of low winds in the selected region under study unlike the adequate solar resource, which will lead to an examination of its feasibility and profitability to compensate for the inactivity of photovoltaic panels in periods of no sunlight. That is a system with fewer photovoltaic panels and storage batteries whereby these should return a full day of autonomy. Two configurations are selected and discussed. The first is composed of photovoltaic panels and storage batteries and the other includes the addition of a wind system in combination with the photovoltaic system with storage but at a higher investment cost than the first. Consequently, this result proves that is preferable to opt for a purely photovoltaic system supported by the storage in this type of site and invalidates the interest of adding micro wind turbines adapted to sites with low wind resources.
The implementation of EU environmental regulations in the energy sector is challenging for the power industry of its member states. The main role is played by documents such as the Winter Package and, especially, the Directive of the European Parliament and of the Council on the emission limits of certain pollutants and the implementation of BAT conclusions in order to achieve the EU’s decarbonization objectives. These regulations impose a greater need to control harmful substances emitted to the atmosphere while using fossil fuels, including hard coal, which is the main fuel for domestic units. At the same time, the decline in domestic fossil fuel production and decrease in the quality of parameters of the hard coal makes it difficult to purchase the proper fuel for power plants. As a consequence, the costs of hard coal increase. The article presents the concept of a mathematical model that can be applied for the optimization of coal supplies. The employment of this model allows one to achieve cost reductions. One of the advantages of the proposed tool, in addition to minimizing the cost of purchase and use of hard coal, is its rational management, especially for companies producing and using hard coal.
The aim of the study was to evaluate the visualization of the rabbit common calcanean tendon and adjacent structures in the high-field magnetic resonance imaging (MRI) of 1.5 T field strength and to compare the results with those previously obtained for the low-field MRI (0.25 T). Eight New Zealand rabbits were used in the post-mortem study and the results indicate that the high-field MRI provides more detailed images only in transverse scans, where the outer outline of the tendon was visualized more accurately. Other analysed structures were imaged with a resolution comparable to the low-field MRI.
The economic envelopes obtained by optimization techniques in open pit mining are transformed into operational phases that are suitable for extraction through ramp designs. This process is performed with the aid of specialized design software, which is still very manual, time consuming and highly dependent on the expertise of the planner. In this paper, we introduce a new methodology based on a mathematical model to automatically propose the design of ramps from the economic envelope of a pushback, with the resulting envelope having the maximum value. The developed model was tested against a real case scenario showing reasonable and useable solutions for the planner. Using this approach, a planner can evaluate several alternatives in a reasonable time before selecting the final design.
The operational mineral deposit reconnaissance tends to evaluate its parameters to conduct safe and profitable production. Particular deposit parameters, important from the point of mineral deposit management, are estimated on the basis of observations carried out by mining geological surveys. These observations usually involve sampling, drilling, laboratory analyses and others. The use of fuzzy description to assess the parameters of the mineral deposit was proposed in the paper. In the fuzzy characteristics, an imprecise descriptive description appeared in place of a particular numerical quantity. This approach was used to description of the ore deposit features (metal content, volume, and metal yield) by assigning them specific characteristic functions, whose distributions were based on basic statistical quantities. Characteristic functions can be used to prepare operational strategies for any configuration of required deposit parameters resulting from the production management needs. For this purpose, selected logical operators of fuzzy sets were used. In the next approach to fuzzy modeling, an opportunity to characterize the deposit in a subjective approach was indicated, where the assessment of the deposit parameters is based on rough, in some way, discretionary observation and evaluation. Such model construction enabled the overall assessment of the deposit from the point of view of any parameters. Through the implementation of appropriate inference rules, adequate fuzzy control planes were obtained, which may also be useful in the context of operational mine strategy planning.
The problem of mathematical modelling and indication of properties of a DIP has been investigated in this paper. The aim of this work is to aggregate the knowledge on a DIP modelling using the Euler-Lagrange formalism in the presence of external forces and friction. To indicate the main properties important for simulation, model parameters identification and control system synthesis, analytical and numerical tools have been used. The investigated properties include stability of equilibrium points, a chaos of dynamics and non-minimum phase behaviour around an upper position. The presented results refer to the model of a physical (constructed) DIP system.
The purpose of this paper is to focus on the loss separation of non-grain-oriented electrical steels used for speed-variable rotating electrical machines. The impact of laser-cutting, used in prototype manufacturing and of flux density harmonics, occurring locally in the lamination, on the loss distribution is studied in detail. Iron losses occurring under operation can physically be separated in different loss components. In this paper, a frequency-based loss model with parameters identified for single-sheet tester specimens, cut in strips of different widths, is therefore used. Moreover, a time-domain approach considers loss distributions occurring from higher harmonics. Hysteresis losses having high sensitivity to cut edge effects are calculated by the well-known Jiles-Atherton model adapting the frequency-based loss parameters. The model is validated by free-curve measurements at a single-sheet tester. It has been shown that the studied elliptical hysteresis model becomes inaccurate particularly for specimens with small strip widths with similar dimensions as teeth of electrical machine laminations. The incorrect mapping of losses occurring from minor hysteresis loops due to higher harmonics is concluded. The results showconsequently that both, the impact of a cut edge effect and local distributions of flux density harmonics need to be considered in terms of accurate iron loss prediction of electrical machine design.
By simulating the actual working conditions of a cable, the temperature variation rule of different measuring points under different load currents was analyzed. On this basis, a three-dimensional finite element model (FEM) was established, and the difference and influence factors between the simulation temperature and the experimental measured value were discussed, then the influence of thermal conductivity on the operating temperature of the conductor layer was studied. Finally, combined with the steady-state thermal conductivity model and the experimental measured data, the relation between thermal conductivity and load current was obtained.
The article presents the possibility of using the Cobb-Douglas production function for planning in a turbulent environment. A case study was carried out – the Cobb-Douglas function was used to examine the condition of the Polish hard coal mining industry and the progress which has been made after undertaking certain activities aimed at increasing the competitiveness of coal companies over recent years. Only the correct and confirmed identification of the causes of irregularities in the production process can allow for the introduction of effective remedies. The effectiveness of the solutions proposed by the author has been confirmed thanks to the simulation during which the impact of the proposed production strategy on the parameters of the CD function was examined. Three variants of production functions models were created and production productivity rates and marginal substitution rates were determined. The results enabled the verification of the progress of restructuring as well as identification of the origin of the observed problems and comparison of the current state with the results of analyses carried out in previous years. Scenarios of possible trend developments for the factors introduced into the function model in order to present remedial measures that could improve the process of hard coal extraction were created. The scenarios were created using the ARIMA class models. Which scenario is the most favourable was determined. A computer program, created by the author, for optimising the level and use of labor resources at the level of the entire coal company has been presented.
This article looks at the semantic space of abstract and concrete concepts from the perspective of distributed models of conceptual representations. It focuses on abstract metaphorical classes and the mechanisms through which these concepts are processed. When the metaphor X is a Y is understood, X is included in the abstract metaphorical class of Y. This metaphorical class is abstract because the most of semantic features of Y are filtered out through a suppressiveoriented mode of processing. It is suggested that abstract metaphorical classes of living things are usually defined by a single or a very small set of semantic features. Therefore, such metaphorical classes are highly abstract. On the other hand, abstract metaphorical classes of nonliving things are defined by a relatively larger cluster of semantic features. Therefore, abstract metaphorical classes of nonliving things have a relatively higher degree of concreteness compared to those of living things. In other words, abstract metaphorical classes of living things and nonliving things are rather different in terms of nature and the structure of semantic space.