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Cioc R.,University of Technology and Humanities in Radom
Lecture Notes in Electrical Engineering | Year: 2017

The paper presents a new approach for determining digital fractional integrator based on the Grünwald–Letnikov differintegrals. The input signal of the integrator includes a sampling time, numerical values and an order of the differintegrals. The present invention pertains generally to the field of integration of digital signals and more particularly to digital signal processing (DSP) and especially to infinite impulse response filters (IIR). © Springer International Publishing AG 2017.


Pajak M.,University of Technology and Humanities in Radom
Risk, Reliability and Safety: Innovating Theory and Practice - Proceedings of the 26th European Safety and Reliability Conference, ESREL 2016 | Year: 2017

The operation position of a technical system is clearly identified by instantaneous values of its cardinal features. The cardinal features can belong to a set of measurable or immeasurable parameters. Despite of the set to which the feature belongs to, its value is specified approximately. In case of measurable features this approximation results from the inaccuracy of measurement devices while in case of immeasurable features it results from the assessment scale digitization. Described inaccuracy should be taken into consideration in the estimation process of the technical system operation position. © 2017 Taylor & Francis Group, London.


Puchalski A.,University of Technology and Humanities in Radom
Journal of Vibroengineering | Year: 2014

In the era of embedded systems the qualifications of engines, machines and on-board vehicle devices into no-fault and fault categories on the basis of vibration signals is the process in conformity with the paradigm of pattern recognitions. The most popular way of looking for vibrodiagnostic features is based on frequency analysis and spectral properties of the observed signals. There is no doubt that the ‘a priori’ knowledge concerning objects being diagnosed is important in gathering information on technical states of mechatronic systems of vehicles. The diagnostic task of vehicle systems solved in the article was considered as the process realised according to properties of statistical signals originated from sensors of vibrations accelerations and not as searching for filtration algorithms of selective time-frequency properties. The data set originated from the observation of time series after angular resampling, without any transformations encompassing a frequency domain, was used in the selection procedure of diagnostic features. Orthogonal decompositions of subspace data matrices allowed to obtain the empirical model of the system. This fact was utilised for non parametric way of generating residual matrix, assessed in no-fault state as being ‘null’. The new non parametric way of diagnosing defects, on the basis of averaged first singular values of residuals determined for the investigated operation states, was also presented. The verified method allowed to perform the statistical analysis of the valve system of the SI engine, based on data originated from the single recording channel. © JVE INTERNATIONAL LTD. JOURNAL OF VIBROENGINEERING 2014.


Jedynak R.,University of Technology and Humanities in Radom
Rheologica Acta | Year: 2015

The main purpose of this paper is to provide an easy-to-use approximation formula for the inverse Langevin function. The mathematical complexity of this function makes it unfeasible for an analytical manipulation and inconvenient for computer simulation. This situation has motivated a series of papers directed on its approximation. The best known solution is given by Cohen. It is used in a lot of statistically based models of rubber-like materials. The formula is derived from rounded Padé approximation [3/2]. The main idea of the presented approach in this paper relies on improvement of the precision of approximation formula for the inverse Langevin function by using multipoint Padé approximation method. We focused our study strongly on obtaining a simple and accurate approximation. It is assumed that the proposed approximation formula may be considered a useful tool for verification of the results obtained in other ways. Our results are supported by investigating several numerical examples. The paper also presents a few applications of computer software named Mathematica which can be used to calculate symbolically one point Padé approximants and numerically multipoint Padé approximants. Using this software, we showed also how to compute higher order derivatives of the inverse function in a simple and elegant way. This issue was discussed by Itskov et al. © 2014 The Author(s).


Wilczek A.,University of Technology and Humanities in Radom
Tribology International | Year: 2015

The aim of this paper is to study the influence of changes in the resistance of transducer connections of a thin-layer sensor on the accuracy of temperature measurement in the EHL contact. A model of the sensor was developed. The calculations were made for the assumed temperature distribution in the contact for two shape types of the transducer - symmetric and asymmetric. The results revealed the importance of a careful selection of transducer's dimensions and the need for the correction of measured temperatures in order to achieve higher measurement accuracy. The largest measurement deviation occurred in the area of maximum temperature. The distribution of temperatures obtained from the measurements with both symmetric and asymmetric transducers did not differ significantly. © 2015 Elsevier Ltd.


Puchalski A.,University of Technology and Humanities in Radom
Mechanical Systems and Signal Processing | Year: 2015

The method of utilising signals of vibration acceleration in the on-line and off-line diagnostics of mechanical defects of internal combustion engines is presented in the paper. The monitored vibration signals of the spark ignition (SI) engine in various maintenance states of the valve system were investigated. The suggested technique is based on mathematical methods of the lower triangular-orthogonal (LQ) factorisation and the singular value decomposition (SVD) of observation subspaces computed on a vibration time series after their angular resampling without any transformations in the frequency domain. The applied algorithm of data processing filters excessive information and allows the selection of diagnostic features (essential from the maintenance point of view) and generates the empirical model and matrix residuals assessed in the no-fault state as being 'zero'. Then, statistical feature vectors, for which the averaged successive singular values of the residuals of the observation subspaces of the vibration signals were assumed as components, were analysed. As a result of this procedure the vectors of lower dimensions reduced to components, allowing the classification of observations within all defined classes, were obtained. On the basis of these vectors a scalar measure - sensitive to the kind of defect - was proposed and verified. © 2014 Elsevier Ltd. All rights reserved.


Saracen A.,University of Technology and Humanities in Radom | Kotwica Z.,University of Technology and Humanities in Radom
International Orthopaedics | Year: 2014

Results: Vertebroplasty significantly diminished the level of pain in 90 % of patients, and half of them were free of pain within 12 hours after surgery. Only 4 % of the patients did not benefit from this type of treatment. During the 24-month follow-up these results changed only slightly, and after two years almost 80 % still benefited, while the number of unsatisfactory results changed from 6 to 9 %. No serious clinical complications were noted; in three patients new fractures appeared during the two year observation period.Conclusions: Vertebroplasty should be seriously taken into account as a primary method of treatment in patients with multiple osteoporotic vertebral compression fractures.Purpose: Vertebral compression fractures cause significant pain and some patients are debilitated by the pain due to the fracture. Conventional surgery carries a high risk and has a poor outcome. Vertebroplasty is a minimally invasive surgical procedure, which in vertebral fractures restores stability and diminishes pain. The aim of the study was to analyse the effectiveness and safety of vertebroplasty in multiple vertebral compression fractures with a 24-month follow-up.Methods: Vertebroplasty was performed in 160 patients with multiple osteoporotic compression fractures under local anaesthesia, using a unilateral transpedicular approach. The level of pain was assessed according to a 10-cm visual analogue scale. The patients were observed for 24 months after surgery. © 2014, The Author(s).


Gorski K.,University of Technology and Humanities in Radom | Przedlacki M.,Warsaw University of Technology
Energy and Fuels | Year: 2014

In this paper, selected physicochemical properties (such as lower heating value (LHV), kinematic viscosity, density, lubricity, cold filter plugging point (CFPP), and cetane number (CN), as well as miscibility of diethyl ether (DEE)/diesel oil blends) were experimentally determined. DEE was added to diesel oil, meeting the requirements of European standard PN-EN 590, in volumetric proportions of 5, 10, 15, and 20 vol %. The LHV, kinematic viscosity, and density of the blends were lower than the values obtained for the tested diesel oil. Especially, it was found that DEE has significant influence on diesel oil viscosity. The addition of merely 5% DEE to diesel oil decreased its viscosity by 26%. It was shown that the lubricity of all tested blends is reduced, but not as significantly as viscosity. It was found that the temperature of the CFPP decreased when DEE was added to diesel oil. The results show that miscibility of all tested fuel blends is excellent in a wide range of temperature changes. The engine experiments were carried out on two different diesel engines. CN values of the tested blends were determined using a Waukesha Co. research engine, according to the procedure presented in European standard EN ISO 5165:2003. It was observed that the addition of DEE slightly increased the CN of the diesel oil. However, it did not have any influence on shortening of the ignition delay period in the tested AD3.152 diesel engine with direct fuel injection. © 2014 American Chemical Society.


Puchalski A.,University of Technology and Humanities in Radom
Journal of Vibroengineering | Year: 2015

The results of the research directed towards solving the task of automatic detection of wear and mechanical defects of internal combustion engines, are presented in the paper. The fractal geometry assumptions were applied in defining diagnostic features depended on the time scale of observations. Investigations were performedby means of the detrended fluctuation analysis. The scaling curves for the fluctuation function and singularityspectra of vibration signals obtained in monitoring a valve system of a spark ignition engine,were determined. The Hurst exponent,multifractality level and singularity exponent of a signal were tested as defects measures. © 2015 JVE International Ltd.


Sobczak M.,University of Technology and Humanities in Radom
Polymer - Plastics Technology and Engineering | Year: 2015

Biodegradable polyurethane elastomers (BioEPUR) are becoming increasingly important as biomaterials because they have excellent chemical, physico-mechanical and biological properties. This review presents the recent developments on BioEPUR and their potential applications in the biomedical and pharmaceutical fields. The aim of this work is to present an overview of the various methods of synthesis and properties of biomedical BioEPUR. Polyurethanes-based aliphatic or cycloaliphatic diisocyanates and polyesters, poly(ester-carbonate)s or copolymers of heterocyclic monomers were discussed. © 2015, Copyright © Taylor & Francis Group, LLC.

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