Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 8
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

In this paper, three methods of sterilisation are compared to determine their usability in nanobubble dispersion sterilisation: filtration, thermal sterilisation and sonication (in two systems: using a sonotrode and sonication bath). Nanobubble dispersions are most commonly generated in non-sterile systems which precludes them from use in most biological research. As a result of this study, filtration was chosen as the best method for nanobubble sterilisation.

Go to article

Authors and Affiliations

Karol Ulatowski
Julia Fiuk
Paweł Sobieszuk
Download PDF Download RIS Download Bibtex

Abstract

Code Excited Linear Prediction (CELP) algorithms are proposed for compression of speech in 8 kHz band at switched or variable bit rate and algorithmic delay not exceeding 2 msec. Two structures of Low-Delay CELP coders are analyzed: Low-delay sparse excitation and mixed excitation CELP. Sparse excitation is based on MP-MLQ and multilayer models. Mixed excitation CELP algorithm stems from the narrowband G.728 standard. As opposed to G.728 LD-CELP coder, mixed excitation codebook consists of pseudorandom vectors and sequences obtained with Long-Term Prediction (LTP). Variable rate coding consists in maximizing vector dimension while keeping the required speech quality. Good speech quality (MOS=3.9 according to PESQ algorithm) is obtained at average bit rate 33.5 kbit/sec.

Go to article

Authors and Affiliations

Przemysław Dymarski
Download PDF Download RIS Download Bibtex

Abstract

The production of high pressure die casts also brings difficulties regarding the processing of the waste material. It is mainly formed by runners, overflows and other foundry supplements used and, in the case of machines using the cold chamber, also the remainder from this chamber. As this material is often returned to the production process, we refer to it as return material. In the production process, it is therefore essential to deal with the proportion issue of return material against primary material that can be added to the melt to maintain the required cast properties. The submitted article monitors the quality properties of the alloy, selected mechanical properties of casts and porosity depending on the proportion of the return material in the melt. At the same time, the material savings are evaluated with regards to the amount of waste and the economic burden of the foundries. To monitor the above-mentioned factors, series of casts were produced from the seven melting process variants with a variable ratio of return to the primary material. The proportion ratio of return material in the primary alloy was adjusted from 100% of the primary alloy to 100% of the return material in the melting process. It has been proven that with the increasing proportion of the return material, the chemical composition of the melt changes, the mechanical properties of the alloy decrease and the porosity of the casts increases. Based on the results of the tests and analyzes, the optimal ratio of return and primary material in the melting process has been determined. Considering the prescribed quality of the alloy and mechanical properties, concerning the economic indicator of the savings, the ratio is set at 70:30 [%] in favor of the primary material.
Go to article

Bibliography

[1] ČSN 04 6509. Pressure die-casting. Terminology (Tlakové lití: Názvosloví). Praha: Český normalizační institut, 1978. 71 p.
[2] ČSN 42 1431. Pressure die castings. Technical conditions (Odlitky tlakové: Technické podmínky). Praha: Český normalizační institut, 1982. 57 p.
[3] Ružbarský, J., Paško, J. & Gašpár, Š. (2014) Techniques of Die casting. Lüdenscheid: RAM-Verlag. ISBN: 978-3-942303-29-3.
[4] Gaspar, S. & Pasko, J. (2016). Technological Aspects of Returnable Material Introducing within Die Casting Technology. Tem Journal-Technology Education Management Informatics. 5(4), 441-445. DOI: 10.18421/TEM54-05.
[5] Majerník, J., Podařil, M., Socha, L., Gryc, K. (2019). Implementation aspects of the remelting material in the production of high pressure die casts on the aluminum based alloys. In 28th International Conference on Metallurgy and Materials, 22-24 May 2019 (pp. 1652-1657). Brno, Czech Republic: TANGER Ltd.
[6] Paško, J. & Gašpár, Š. (2014). Technological factors of die casting. Lüdenscheid: RAM-Verlag. ISBN: 978-3-942303-25-5.
[7] Capuzzi, S. & Timelli, G. (2018). Preparation and melting of scrap in aluminum recycling: A review. Metals. 8(4), 249. DOI: 10.3390/met8040249.
[8] Mwema F.M. et al. (2019). Wear characteristics of recycled cast Al-6Si-3Cu alloys. Tribology in Industry. 41(4), 613-621. DOI: 10.24874/ti.2019.41.04.13.
[9] Lazaro-Nebreda J., Patel, J.B., Chang, I.T.H., Stone, I.C., Fan Z. (2019). Solidification processing of scrap Al-alloys containing high levels of Fe. In Joint 5th International Conference on Advances in Solidification Processes, ICASP 2019 and 5th International Symposium on Cutting Edge of Computer Simulation of Solidification, Casting and Refining, CSSCR 2019, 17-21 June 2019 (Article number 012059). Salzburg: Institute of Physics Publishing. DOI: 10.1088/1757-899X/529/1/012059.
[10] Noga, P., Tuz, L., Żaba, K., & Zwoliński, A. (2021). Analysis of microstructure and mechanical properties of alsi11 after chip recycling, co-extrusion, and arc welding. Materials. 14(11), 3124. DOI: 10.3390/ma14113124.
[11] Bolibruchová, D. & Matejka, M. (2018). Analysis of microstructure changes for AlSi9Cu3 Alloy caused by remelting. Manufacturing Technology. 18(6), 883-888. DOI: 10.21062/ujep/195.2018/a/1213-2489/mt/18/6/883.
[12] Bjurenstedt, A., Seifeddine, S. & Jarfors, A.E.W. (2016). The effects of Fe-particles on the tensile properties of Al-Si-Cu alloys. Metals. 6(12), 314. DOI: 10.3390/met6120314.
[13] Fu, J., Yang, D. & Wang, K. (2018). Correlation between the liquid fraction, microstructure and tensile behaviors of 7075 aluminum alloy processed by recrystallization and partial remelting (RAP). Metals. 8(7), 508. DOI: 10.3390/met8070508.
[14] Krolo, J., Lela, B., Ljumović, P. & Bagavac, P. (2019). Enhanced mechanical properties of aluminium alloy EN AW 6082 recycled without remelting. Technicki Vjesnik. 26(5), 1253-1259. DOI: 10.17559/TV-20180212160950.
[15] Wang, K. at al. (2018). Characterization of microstructures and tensile properties of recycled Al-Si-Cu-Fe-Mn alloys with individual and combined addition of titanium and cerium. Scanning. 2018, 3472743. DOI: 10.1155/2018/3472743.
[16] Matejka, M., Bolibruchová, D. & Kuriš, M. (2021). Crystallization of the structural components of multiple remelted AlSi9Cu3 alloy. Archives of Foundry Engineering. 21(2), 41-45. DOI: 10.24425/afe.2021.136096.
Go to article

Authors and Affiliations

S. Gaspar
1
ORCID: ORCID
J. Majerník
2
ORCID: ORCID
A. Trytek
3
ORCID: ORCID
M. Podaril
2
ORCID: ORCID
Z. Benova
2
ORCID: ORCID

  1. Faculty of Manufacturing Technologies of the Technical University of Košice with the seat in Prešov, Slovak Republic
  2. Institute of Technology and Business in České Budějovice, Czech Republic
  3. The Faculty of Mechanics and Technology in Stalowa Wola, Poland
Download PDF Download RIS Download Bibtex

Abstract

The paper presents the results of analysis of duration of precipitation sequences and the amounts of precipitation in in-dividual sequences in Legnica. The study was aimed at an analysis of potential trends and regularities in atmospheric pre-cipitations over the period of 1966–2015. On their basis a prediction attempt was made for trends in subsequent years. The analysis was made by fitting data to suitable distributions – the Weibull distribution for diurnal sums in sequences and the Pascal distribution for sequence durations, and then by analysing the variation of the particular indices such the mean value,variance and quartiles. The analysis was performed for five six-week periods in a year, from spring to late autumn, ana-lysed in consecutive five-year periods. The trends of the analysed indices, observed over the fifty-year period, are not sta-tistically significant, which indicates stability of precipitation conditions over the last half-century.

Go to article

Authors and Affiliations

Teresa Jakubczyk
Download PDF Download RIS Download Bibtex

Abstract

Inductive loop sensors are widely used for detection of presence, measurement of parameters as well as classification of vehicles. Vehicle classification may be performed based on their magnetic profiles. The magnetic profile is a signal which is proportional to the resultant of an impedance change of the sensor, caused by the measured object (the changes are minor - of the order of 1%). Generator and bridge circuits are most commonly used as conditioning circuits for such sensors. As a result we can obtain one output signal proportional to total changes of sensor parameters (R and L). In this paper, a modified bridge circuit that allows independent measurement of the components (R and L) of the sensor's impedance, has been proposed. With that provided, it is possible to receive broader information on the object, which allows higher classification resolution. This paper provides the concept of a circuit, model testing results, processing algorithms used and the test results of a real circuit.

Go to article

Authors and Affiliations

Zbigniew Marszałek
Ryszard Sroka
Marek Stencel
Download PDF Download RIS Download Bibtex

Abstract

Abstract This paper deals with the application of the Radial Basis Function (RBF) networks for the induction motor fault detection. The rotor faults are analysed and fault symptoms are described. Next the main stages of the design methodology of the RBF-based neural detectors are described. These networks are trained and tested using measurement data of the stator current (MCSA). The efficiency of developed RBF-NN detectors is evaluated. Furthermore, influence of neural networks complexity and parameters of the RBF activation function on the quality of data classification is shown. The presented neural detectors are tested with measurement data obtained in the laboratory setup containing the converter-fed induction motor (IM) and changeable rotors with a different degree of damages
Go to article

Authors and Affiliations

M. Kamiński
C.T. Kowalski
Download PDF Download RIS Download Bibtex

Abstract

The paper presents a tool for accurate evaluation of high field concentrations near singular lines, such as contours of cracks, notches and grains intersections, in 3D problems solved the BEM. Two types of boundary elements, accounting for singularities, are considered: (i) edge elements, which adjoin a singular line, and (ii) intermediate elements, which while not adjoining the line, are still under strong influence of the singularity. An efficient method to evaluate the influence coefficients and the field intensity factors is suggested for the both types of the elements. The method avoids time expensive numerical evaluation of singular and hypersingular integrals over the element surface by reduction to 1D integrals. The method being general, its details are explained by considering a representative examples for elasticity problems for a piece-wise homogeneous medium with cracks, inclusions and pores. Numerical examples for plane elements illustrate the exposition. The method can be extended for curvilinear elements.

Go to article

Authors and Affiliations

L. Rybarska-Rusinek
Download PDF Download RIS Download Bibtex

Abstract

The Author analyzes Professor Józef Andrzej Gierowski's cooperation with the Wrocław academic community after this eminent Polish historian moved to Cracow in the years 1965-2007.
Go to article

Authors and Affiliations

Krystyn Matwijowski

This page uses 'cookies'. Learn more