This research work is focused on examining the turning behavior of Incoloy 800H superalloy by varying important cutting parameters. Incoloy 800H is an Iron- Nickel-Chromium based superalloy; it can withstand high temperature (810°C), high oxidization and corrosion resistance. But, it is difficult to turn in conventional machines and hence the present work was carried out and investigated. Experiments were conducted based on the standard L27 orthogonal array using uncoated tungsten inserts. The cutting force components, namely, feed force (Fx), thrust force (Fy) and cutting force (Fz); surface roughness (Ra) and specific cutting pressure (SCPR) were measured as responses and optimized using Taguchi-Grey approach. The main effects plots and analysis of mean (ANOM) were performed to check the effect of turning parameters and their significance on responses of cutting forces in all the direction (FX, FY, FZ), the surface roughness (Ra) and specific cutting pressure (SCPR). The tool wear and machined surfaces were also investigated using white light interferometer and SEM.
The paper presents the mathematical models of dual stator squirrel-cage induction motor, formulated in phase coordinate system and in general transformed space vector form. The two types of models of dual stator induction motor are considered. The control systems of field-oriented control (IFOC and DFOC) and direct torque control (DTC) of the dual stator induction motor have been described and discussed.
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.
The paper presents modeling and simulation results of the operation of a three-phase fluidized bed bioreactorwith partial recirculation of biomass. The proposed quantitative description of the bioreactor takes into account biomass growth on inert carriers, microorganisms decay and interphase biomass transfer. Stationary characteristics of the bioreactor and local stability of steady-stateswere determined. The influence of microbiological growth kinetics on the multiplicity of steady-states was discussed. The relationship between biofilm growth and boundaries of fluidized bed existence was shown.
The lumbosacral region of the spine is the most susceptible to pathology in large breed dogs. The most common pathologies of this segment include intervertebral disc disease, distortion of vertebrae, narrowing of the lumbosacral canal and congenital defects of the spine. The aim of this study is to develop a mathematical model describing the height of each lumbosacral vertebra in the dog in relation to the position of the vertebra. For the mathematical analysis we used the results of two measurements for each lumbar vertebra. The first measurement was made from the top of the spinous process to the center of the spinal cord. The second measurement was made from the center of the body of one vertebra to the center of the body of the next one. It is possible to determine an approximate mathematical model that would be uniform for the entire species and would connect the height of the lumbar vertebrae with their location for every breed of the domestic dog. Despite the considerable differences in the constitutional type (small, medium and large breeds), the morphology of the lumbosacral region of the spine exhibits similar proportions. Therefore, it is possible to assess an anomaly of this spinal region objectively. These findings suggest that it is possible to determine an approximate mathematical model that would be uniform for the entire species. The present study was carried out as part of a larger project. This particular work is a pilot study.
The problems of mathematical modelling of vibration signal for bearings with specific geometrical structure or defect is important insofar as there are no model bearings (to facilitate carrying out a calibration procedure for industrial measurement systems). It is even more so that there are no precise reference systems to which we would compare the results. This article presents a general outline of the most important studies on modelling of vibrations in rolling bearings. Papers constituting the basis for the most recent studies and a review of articles from the past few years have been considered here. Five different models have been analyzed in detail in order to show the directions of the latest studies. Completed analysis presents different viewpoints on the issue of modelling a rolling bearing operation. This overview article makes it possible to derive the final conclusion that in order to include all factors affecting bearing vibrations, even those ignored in the most recent models, it is necessary to carry out practical statistical research including the principles of multicriteria statistics. This approach will facilitate developing a versatile model, also applicable to predicting vibrations of a new bearing just manufactured in a factory.
Skin dynamic termography supplemented by a mathematical model is presented as an objective and sensitive indicator of the skin prick test result. Termographic measurements were performed simultaneously with routine skin prick tests. The IR images were acquired every 70 s up to 910 s after skin prick. In the model histamine is treated as the principal mediator of the allergic reaction. Histamine produces vasolidation and the engorged vessels are responsible for an increase in skin temperature. The model parameters were determined by fitting the analytical solutions to the spatio-temporal distributions of the differences between measured and baseline temperatures. The model reproduces experimental data very well (coefficient of determination = 0.805÷0.995). The method offers a set of parameters to describe separately skin allergic reaction and skin reactivity. The release of histamine after allergen injection is the best indicator of allergic response. The diagnostic parameter better correlates with the standard evaluation of a skin prick test (correlation coefficient = 0.98) than the result of the thermographic planimetric method based on temperature and heated area determination (0.81). The high sensitivity of the method allows for determination of the allergic response in patients with the reduced skin reactivity.
In the projects of protection of soil-water environment there is a need to combine and process large amount of information from various disciplines to estimate parameters of phenomena and to determine the range and time table of necessary undertakings.
Due to complex assessment of processes taking place in aquifers, mathematical modeling is the best tool supporting evaluation off pollution in the ground water environment. It is also an effective method of forecasting the risk associated with the harmful impact of objects polluting grounds and grounds waters.
Significant application of mathematical modeling is the use for the enlargement of information gathered in the process of recognition and assessment of condition that prevail in soil-water environment. Results of modeling, if appropriately presented, could be an important element of decision support system in environmental management.
This paper describes procedures for developing an environmental remediation decision support system by linking CADD and GIS software with the hydro geological flow and transport models.
The agrarian process includes many industrial phenomena and events. The goal of economics as a science is to precisely detect and describe the relationships between various market mechanisms. These phenomena can be presented as the desire “to describe reality in terms of systems, their components and relationships, both between components of the system and between different systems” (Jankowski 1997). The energy sector is a special field among many areas of the national economy, and the products of this sector have a major impact on the branches of the economy and the mechanisms of action occurring in them. The publication is devoted to the construction of a mathematical model used to support the energy policy of local government units. The aim of the study is to build a mathematical model of energy production, taking the development potential of renewable energy into account, as well as to propose the desired direction of energy policy development in the analyzed periods to the regional authorities and to offer a model for creating an energy policy in other local government units: poviats, communes. Until now, few authors have comprehensively dealt with this issue. To date, no detailed research has been published on issues related to renewable energy development and the use of mathematical methods in the construction of the energy production model in local government units. The undertaken research is a contribution to the development of knowledge about alternative energy sources in the energy margin.