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Abstract

A double balanced passive mixer-based receiver operating in the 3-5 GHz UWB for medical applications is described in this paper. The receiver front-end circuit is composed of an inductorless low noise amplifier (LNA) followed by a fully differential voltage-driven double-balanced passive mixer. A duty cycle of 25% was chosen to eliminate overlap between LO signals, thereby improving receiver linearity. The LNA realizes a gain of 25.3 dB and a noise figure of 2.9 dB. The proposed receiver achieves an IIP3 of 3.14 dBm, an IIP2 of 17.5 dBm and an input return loss (S11) below -12.5dB. Designed in 0.18μm CMOS technology, the proposed mixer consumes 0.72pW from a 1.8V power supply. The designed receiver demonstrated a good ports isolation performance with LO_IF isolation of 60dB and RF_IF isolation of 78dB.
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Authors and Affiliations

Thaar A. Kareem
1
Hatem Trabelsi
1

  1. Systems Integration & Emerging Energies Laboratory, Electrical Engineering Department, National Engineers School of Sfax, University of Sfax, Sfax, Tunisia
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Abstract

The article discusses issues related to the melting of grey and ductile cast iron in terms of metallurgical quality. The derivative and thermal analysis (DTA) was used to assess this quality. The article presents the results of research carried out in industrial conditions and analysed by the Itaca system. In the paper, the effect of the furnace type, the charge materials and the inoculation process on the parameters characterising the cast iron being melted was analysed. The most important of these are the minimum eutectic temperature (Te min), the liquidus temperature (T liquidus) and the nucleation rate. The results of the research and calculations are shown in graphs and as dependencies. Some of DTA results were compared to the microstructure analysis results. The article shows that the derivative and thermal analysis is a very effective tool in the assessment of the metallurgical quality of cast iron. It is a very good addition to chemical analysis. Based on the results of the research, it was concluded that a very high correlation exists between the rate of nucleation (DTA) and the number of graphite nuclei (microstructure analysis). Furthermore, it was also found that an improvement in nucleation could be achieved by ensuring a high value of carbon equivalent (CE) and, above all, by conducting the primary and secondary inoculation processes, respectively.
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Bibliography

[1] Stefanescu, D.M., Suarez, R. & Kim S.B, (2020). 90 years of thermal analysis as a control tool in the melting of cast iron. China Foundry. 17(2), 69-84. https://doi.org/10.1007/s41230-020-0039-x.
[2] Jura, S., Sakwa, J. & Borek, K. (1980). Application of thermal and differential analysis for determination of chemical composition parameters. Krzepnięcie Metali i Stopów. 3, 16-24. (in Polish).
[3] Jura, S., Sakwa, J. & Borek, K. (1980). Differential analysis of solidification and crystallization processes of gray cast iron. Krzepnięcie Metali i Stopów. 3, 25-35. (in Polish).
[4] Jura, Z. & Jura, S. (1990). Calorimetric curve and heat source in thermal and derivational analysis of cast iron solidification process. Krzepnięcie Metali i Stopów. 16, 126-139. (in Polish).
[5] Jura, Z. & Jura, S. (1996). The theory of the TDA method in the study of Al alloys. Krzepnięcie Metali i Stopów. 28, 57-88. (in Polish).
[6] Jura, S., Studnicki, A., Przybył, M. & Jura, Z. (2001). Application of the ATD method to assess the quality of ductile cast iron. Archiwum Odlewnictwa. 1(1), 93-102. (in Polish).
[7] Gawroński, J., Szajnar, J., Jura, Z. & Studnicki, A. (2004). Professor Stanisław Jura, creator of the theory and industrial applications of diagnostics and wear of metals and alloys. Archiwum Odlewnictwa. 4(SI 16), 1-74. (in Polish).
[8] Pietrowski, S. & Władysiak, R. (1996). TDA Inspection of piston silumins. Krzepnięcie Metali i Stopów. 28, 160-173. (in Polish).
[9] Pietrowski, S. & Gumienny, G. (2002). Methodology for preparing the quality assessment of ductile cast iron using the TDA method. Archiwum Odlewnictwa. 2(6). (in Polish).
[10] Pietrowski, S. & Gumienny, G. (2002). Evaluation of the quality of ductile cast iron EN-GJS-400-15 by the TDA method. Archiwum Odlewnictwa. 2(6), 257-268. (in Polish).
[11] Chisamera, M., Riposan, I., Stan, S., Stefan, E. & Costache, G. (2009). Thermal analysis control of in-mould and ladle inoculated grey cast irons. China Foundry. 6(2), 145-151.
[12] Erturka, S.O., Kumruoglub, L.C., Ozel, A. (2017). Determination of feederless casting limits by thermal analysis in cast iron. Acta Physica Polonica A. 131(3), 370-373. DOI: 10.12693/APhysPolA.131.370.
[13] Seidu, S.O. (2013). Thermal analysis of preconditioned ductile cast iron. International Journal of Current Engineering and Technology. 3(3), 813-818. ISSN 2277-4106.
[14] Cojocaru, A.M., Riposan, I. & Stan, S. (2019). Solidification influence in the control of inoculation effects in ductile cast irons by thermal analysis. Journal of Thermal Analysis and Calorimetry.138, 2131-2143. https://doi.org/10.1007/s10973-019-08808-2.
[15] Petrus, Ł., Bulanowski, A., Kołakowski, J., Brzeżański, M., Urbanowicz, M., Sobieraj, J., Matuszkiewicz, G., Szwalbe, L., Janerka, K. (2020). The influence of selected melting parameters on the physical and chemical properties of cast iron. Archives of Foundry Engineering. 20(1), 105-110. DOI: 10.24425/afe.2020.131290.
[16] Petrus, Ł., Bulanowski, A., Kołakowski, J., Sobieraj, J., Paruch, T., Urbanowicz, M., Brzeżański, M., Burdzy, D. & Janerka. K. (2021). Importance of TDA thermal analysis in an automated metallurgical process. Journal of Casting & Materials Engineering. 5(4), 89-93. https://doi.org/10.7494/ jcme.2021.5.4.89.
[17] ProserviceTech. Retrieved June, 30, 2022 from http://www.proservicetech.it/itacax-thermal-analysis-final-iron-quality-control/.
[18] Novacast. Retrieved June, 30, 2022 from https://www.novacast.se/product/atas/.
[19] Heraeus. Retrieved June, 30, 2022 from https://www.heraeus.com/en/hen/products_and_solutions_hen/foundry/thermal_analysis/thermal_analysis.html.
[20] Vesuvius. Retrieved June, 30, 2022 from https://www.vesuvius.com/content/dam/vesuvius/corporate/Our-solutions/our-solutions-master-english/foundry/Newsletter/Issue2/FP-new-issues/FERROLAB%20V.pdf.

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Authors and Affiliations

J. Kołakowski
1
ORCID: ORCID
M. Brzeżański
1
ORCID: ORCID
D. Burdzy
1
ORCID: ORCID
J. Sobieraj
1
M. Urbanowicz
1
T. Paruch
1
K. Janerka
2
ORCID: ORCID

  1. “Śrem” Iron Foundry Sp. z o.o., ul. Staszica 1, 63-100 Śrem, Poland
  2. Department of Foundry Engineering, Silesian University of Technology, ul. Towarowa 7, 44-100 Gliwice, Poland
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Abstract

Wielofunkcyjne zbiorniki zaporowe odgrywają ważną rolę w zaopatrzeniu w wodę, również pitną, a także w nawadnianiu, hydroenergetyce, ochronie przeciwpowodziowej, rekreacji, żegludze itd. Jednocześnie często wywierają niekorzystny, choć niewidoczny wpływ na środowisko i lokalną bioróżnorodność. Owe „brudne sekrety” to m.in. depozycja osadów, zakwity cyjanobakterii i emisja gazów cieplarnianych.

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Authors and Affiliations

Silke Wieprecht
Zespół projektu CHARM
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Abstract

This paper adopts a fractional calculus perspective to describe a non-linear electrical inductor. First, the electrical impedance spectroscopy technique is used for measuring the impedance of the device. Second, the experimental data is approximated by means of fractional-order models. The results demonstrate that the proposed approach represents the inductor using a limited number of parameters, while highlighting its most relevant characteristics.

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Authors and Affiliations

A.M. Lopes
J.A. Tenreiro Machado
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Abstract

Professor architect Juliusz Żórawski (1898–1967) is presented in this memorial text by one of his close pupils and collaborators. The author describes the air of lectures on architectural design given by Żórawski, and the mood prevailing in the chair headed by Professor at the Faculty of Architecture of the Cracow University of Technology during the first 20 years after the WW II. The case of the city house in Warsaw built in 1937 proves the avant-garde role of Żórawski in the Polish architecture between the two wars. The original text prepared in 1968 is published here for the first time.
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Authors and Affiliations

Janusz Ballenstedt

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