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Abstract

The starting point of the study on the problems, dilemmas and hopes for effective implementation of revitalization projects in Polish cities was the conviction that revitalization is one of the processes affecting the development and changes in the spatial and functional fabric of cities. Revitalization is defined as a deliberate and purposeful process, the effect of which is to restore life in the dysfunctional and degraded parts of cities. Taking up such a topic required an answer to the question about the nature of revitalization and its aspects. The focus of the study was on the problems of revitalization that stem from the legal and socio-economic situation and the dilemmas faced by local government authorities of Polish cities. The introduction to these considerations is the brief outline of the revitalization of Polish cities in the period after World War II, while the conclusion deals with the fears and hopes related to revitalization activities that are presently initiated. The discussion takes into account the existing, critically assessed, legal regulations on revitalization.

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Authors and Affiliations

Krzysztof Gasidło
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Abstract

Understanding the Cenozoic tectonic evolution of grabens rich in lignite is important in the context of the accumulation of ~40–650 m of peat, as well as the exploitation of later formed lignite seams with a thickness of ~20–250 m. Six such areas were selected for a detailed palaeotectonic analysis: the Gostyń, Szamotuły, Legnica, Zittau, Lubstów, and Kleszczów grabens. During the analysis, borehole data were used, taking into account the compaction of peat at the transition to lignite, in order to reconstruct the magnitude of the total subsidence. This made it possible to distinguish between regional (covering areas also outside the grabens) and local (occurring only in the grabens) tectonic movements, and among the latter, tectonic and compactional subsidence. The hypothetical palaeosurface of the mires was reconstructed based on the lignite decompaction. As a result, it was possible to determine whether the examined peat/lignite seams underwent post-depositional uplift and/or subsidence. Between one (Gostyń Graben) and four (Zittau Basin and Kleszczów Graben) stages of tectonic subsidence were distinguished in the studied lignite-bearing areas. In the case of the Zittau Basin, as well as the Lubstów and Kleszczów grabens, post-depositional stages of tectonic uplift were also indicated. Like the boundaries of lithostratigraphic units, the successive stages of the Cenozoic tectonic development of the examined grabens are diachronic.
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Authors and Affiliations

Marek Widera
1

  1. Institute of Geology, Adam Mickiewicz University, Krygowski 12, 61-680 Poznań, Poland
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Abstract

The article describes the idea of a compact city, due to the needs and capabilities of contemporary Polish cities, with an emphasis on the Silesia region. Special attention has been paid to the possibility of increasing the cities’ density and several examples have been shown to present the possibilities of densifying the cities with new housing investments. Also, the article presents the studies that indicate the capacity for the internal development of selected Silesian cities: Katowice and Gliwice. The article ends with the recommendations for cities to become more compact.

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Authors and Affiliations

Agata Twardoch
Tomasz Bradecki
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Abstract

The present paper describes the results of experimental investigations of heat transfer during condensation of R134a, R404A and R407C in pipe minichannels with internal diameters 0.31-3.30 mm. The results concern investigations of the local heat transfer coefficient. The results were compared with the correlations proposed by other authors. Within the range of examined parameters of the condensation process in minichannels made of stainless steel, it was established that the values of the heat transfer coefficient may be described with Akers et al., Mikielewicz and Shah correlations within a limited range of the mass flux density of the refrigerant and the minichannel diameter. On the basis of experimental investigations, the authors proposed their own correlation for the calculation of local heat transfer coefficient.
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Authors and Affiliations

Tadeusz Bohdal
Henryk Charun
Małgorzata Sikora
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Abstract

In the paper the problem of modelling thermal properties of semiconductor devices with the use of compact models is presented. This class of models is defined and their development over the past dozens of years is described. Possibilities of modelling thermal phenomena both in discrete semiconductor devices, monolithic integrated circuits, power modules and selected electronic circuits are presented. The problem of the usefulness range of compact thermal models in the analysis of electronic elements and circuits is discussed on the basis of investigations performed in Gdynia Maritime University.

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Authors and Affiliations

Krzysztof Górecki
Janusz Zarębski
Paweł Górecki
Przemysław Ptak
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Abstract

The paper presents the effect of manganese on the crystallization process, microstructure and selected properties: cast iron hardness as well as ferrite and pearlite microhardness. The compacted graphite was obtained by Inmold technology. The lack of significant effect on the temperature of the eutectic transformation was demonstrated. On the other hand, a significant reduction in the eutectoid transformation temperature with increasing manganese concentration has been shown. The effect of manganese on microstructure of cast iron with compacted graphite considering casting wall thickness was investigated and described. The nomograms describing the microstructure of compacted graphite iron versus manganese concentration were developed. The effect of manganese on the hardness of cast iron and microhardness of ferrite and pearlite were given.

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Authors and Affiliations

Grzegorz Gumienny
ORCID: ORCID
B. Kurowska
ORCID: ORCID
P. Just
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Abstract

Road infrastructure is aimed to be sustainable construction in today’s condition of heavy traffic. Depending on geotechnical characteristics of soils there are chosen adequate techniques for compaction, meaning: type of compaction, equipment, compaction parameters and, if possible, computer aided acquisition and processing of data. This paper presents research results on the vibratory roller compaction process of road soils, from the point of view of process mathematically modeling and statistically modeling of process parameters interdependence. The obtained regression model is innovative one and fit for further application in optimization (by AI and IoT) of the compaction process. Good correlation of all the results (self-pulsation values) proves the adequate assumptions for both modeling and experimenting. Further development of this research is intended to develop a special software for direct correlation of road geographical position and soil characteristics to the compaction process parameters optimum values.
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Authors and Affiliations

Dragoş Căpăînă
1
ORCID: ORCID
Marilena Cristina Niţu
1
ORCID: ORCID
Mihaiela Iliescu
1
ORCID: ORCID

  1. Institute of Solid Mechanics, Romanian Academy, Constantin Mille 15, Bucharest, Romania
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Abstract

The paper presents research results of bond tests in completely concrete encased steel Isection columns made of self-compacting concrete (SCC). The results of push-out tests obtained by elements made of SCC were compared with those elements, which were made of vibrated concrete. The influence of selected factors on resistance to the vertical shear was considered in this study. The analysis of research results shows that the resistance to the vertical shear between steel I-section and SCC concrete depends on distance between stirrups and concrete age. Shrinkage has important influence on interfacial bond forces. The test results were compared with a recommendations given in the Design code – Eurocode 4. This standard can be used only for composite elements made of lightweight and vibrated concrete. In the case of completely concrete encased I-section composite columns the shear resistance after 28 days and after concrete shrinkage was higher than design resistance strength given in the standard. This means that the design value of the shear strength given in the standard should be verified and checked, if it can be applied to elements made of SCC concrete. Further tests should be carried out to determine the value of shear resistance for such elements.
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Authors and Affiliations

Magdalena Szadkowska
1
ORCID: ORCID
Elżbieta Szmigiera
1
ORCID: ORCID

  1. Warsaw University of Technology, Faculty of Civil Engineering, Al. Armii Ludowej 16, 00-637 Warsaw, Poland
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Abstract

The study investigates the effect of Portland cement and ground granulated blast furnace slag (GGBFS) added in changed proportions as stabilising agents on soil parameters: uniaxial compressive strength (UCS), Proctor compactness and permeability. The material included dredged clayey silts collected from the coasts of Timrå, Östrand. Soil samples were treated by different ratio of the stabilising agents and water and tested for properties. Study aimed at estimating variations of permeability, UCS and compaction of soil by changed ratio of binders. Permeability tests were performed on soil with varied stabilising agents in ratio H WL B (high water / low binder) with ratio 70/30%, 50/50%, and 30/70%. The highest level of permeability was achieved by ratio 70/30% of cement/slag, while the lowest - by 30/70%. Proctor compaction was assessed on a mixture of ash and green liquor sludge, to determine optimal moisture content for the most dense soil. The maximal dry density at 1.12 g/cm 3 was obtained by 38.75% of water in a binder. Shear strength and P-wave velocity were measured using ISO/TS17892-7 and visualised as a function of UCS. The results showed varying permeability and UCS of soil stabilised by changed ratio of CEM II/GGBS.
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Authors and Affiliations

Per Lindh
1 2
ORCID: ORCID
Polina Lemenkova
3
ORCID: ORCID

  1. Swedish Transport Administration, Malmö, Sweden
  2. Lund University (Lunds Tekniska Högskola, LTH), Faculty of Engineering, Department of Building and Environmental Technology, Division of Building Materials, Lund, Sweden
  3. Université Libre de Bruxelles (ULB), École polytechnique de Bruxelles (Brussels Faculty of Engineering), Laboratory of Image Synthesis and Analysis, Brussels, Belgium
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Abstract

The present paper describes results of experimental investigations of pressure drop during the condensation of R134a, R404a and R407C refrigerants in pipe minichannels with internal diameter 0.31-3.30 mm. The results concern investigations of the mean and local pressure drop in single minichannels. The results of experimental investigations were compared with the calculations according to the correlations proposed by other authors. A pressure drop during the condensation of refrigerants is described in a satisfactory manner with Friedel and Garimella correlations. On the basis of the experimental investigations, the authors proposed their own correlation for calculation of local pressure drop during condensation in single minichannels.
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Authors and Affiliations

Tadeusz Bohdal
Henryk Charun
Małgorzata Sikora
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Abstract

Internet of Things (IoT) will play an important role in modern communication systems. Thousands of devices will talk to each other at the same time. Clearly, smart and efficient hardware will play a vital role in the development of IoT. In this context, the importance of antennas increases due to them being essential parts of communication networks. For IoT applications, a small size with good matching and over a wide frequency range is preferred to ensure reduced size of communication devices. In this paper, we propose a structure and discuss design optimization of a wideband antenna for IoT applications. The antenna consists of a stepped-impedance feed line, a rectangular radiator and a ground plane. The objective is to minimize the antenna footprint by simultaneously adjusting all geometry parameters and to maintain the electrical characteristic of antenna at an acceptable level. The obtained design exhibits dimensions of only 3.7 mm × 11.8 mm and a footprint of 44 mm2, an omnidirectional radiation pattern, and an excellent pattern stability. The proposed antenna can be easily handled within compact communication devices. The simulation results are validated through measurements of the fabricated antenna prototype.

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Authors and Affiliations

Muhammad Aziz ul Haq
Sławomir Kozieł
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Abstract

In this paper, a novel structure of a compact UWB slot antenna and its design optimization procedure has been presented. In order to achieve a sufficient number of degrees of freedom necessary to obtain a considerable size reduction rate, the slot is parameterized using spline curves. All antenna dimensions are simultaneously adjusted using numerical optimization procedures. The fundamental bottleneck here is a high cost of the electromagnetic (EM) simulation model of the structure that includes (for reliability) an SMA connector. Another problem is a large number of geometry parameters (nineteen). For the sake of computational efficiency, the optimization process is therefore performed using variable-fidelity EM simulations and surrogate-assisted algorithms. The optimization process is oriented towards explicit reduction of the antenna size and leads to a compact footprint of 199 mm2 as well as acceptable matching within the entire UWB band. The simulation results are validated using physical measurements of the fabricated antenna prototype.
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Authors and Affiliations

Sławomir Koziel
Adrian Bekasiewicz
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Abstract

The compactness of dimension stone blocks was previously controlled through various methods that were partially based on personal experiences, acoustic and visual observance of materials. With the development of technology, the ultrasonic pulse method is frequently used for the examination of stone test pieces and with an analysis of acquired data through the tomography method, the compactness is determined. The monolith stone blocks that are found at a site contain hidden discontinuities. The technique of data acquisition and the use of various instruments enable a good overview of the block interior. With an increased number of measurements, a suitable classification is prepared that helps reduce modification costs and increases the quality of stone blocks. The control methodology of compactness is based on the passage of longitudinal waves through the stone block without damaging the block during control. High differences in speed show irregularities in the material. With the observation system, we can prepare a tomography of the measured profiles that show us the locations of irregularities that should be observed more closely. During in situ measurements, the data for comparison with measured results are acquired. Determination of critical locations is of extreme importance before the processing of the block into smaller stone products or during the reconstruction of older stone elements or sculptures. The purpose of “in situ” measurements is to prepare a simple and fast method for the evaluation of materials compactness and for production work.

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Authors and Affiliations

Andrej Kos
Jože Kortnik
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Abstract

Plastic mulch provides a range of benefits including helping modulate soil temperature, reduce soil erosion, evaporation, fertilizer leaching and weed problems and increasing the quality and yields of the product. But when the crops are harvested, plastic mulch needs to be removed from the ground for disposal. Otherwise, these wastes are mixed with the soil and have a negative impact on yields by reducing the access of nutrients and moisture in the soil. The purpose of the current study is, therefore, to propose a roller for plastic mulch retriever which is applicable when the crops are harvested, and the plastic mulch needs to be removed from the ground for disposal. The winding mechanism of the plastic mulch retriever performs the main function and must have the high-quality performance of the winding operation in the removal technology. Research based on requirements of tensile strength test method and changes of strength characteristics of plastic mulch from various factors under natural conditions. The coefficient of compaction of the used plastic mulch (Krel), was the ratio of the diameter of the standard plastic mulch which was wound in the factory to the diameter of the used plastic mulch during the winding.
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Authors and Affiliations

Kanat M. Khazimov
1
ORCID: ORCID
Adilkhan K. Niyazbayev
1
ORCID: ORCID
Zhanbota S. Shekerbekova
2
ORCID: ORCID
Aigul A. Urymbayeva
2
ORCID: ORCID
Gulzhanat A. Mukanova
2
ORCID: ORCID
Tursunkul A. Bazarbayeva
2
ORCID: ORCID
Vladimir F. Nekrashevich
3
ORCID: ORCID
Marat Zh. Khazimov
1 2 4
ORCID: ORCID

  1. Kazakh National Agrarian University, Faculty of IT – Technology, Automation and Mechanization of Agro-Industrial Complex, Valikhanov St 137, Almaty 050000, Kazakhstan
  2. Al-Farabi Kazakh National University, Faculty of Geography and Environmental Sciences, Almaty, Kazakhstan
  3. Ryazan State Agrotechnological University, Ryazan, Russia
  4. Almaty University of Power Engineering and Telecommunications, Faculty of Heat Power Engineering and Heating Engineering, Almaty, Kazakhstan
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Abstract

The aim of the study was to indicate the influence of consolidation processes on microstructure and selected mechanical properties of powder metallurgy Ti-5Al-5Mo-5V-3Cr alloy, which was produced by blending of elemental powders method. Morphology of the mixture and its ingredients were examined using scanning electron microscopy. The consolidation of powders mixture was conducted using two approaches. The first consisted of the uniaxial hot pressing process, the second included two steps – uniaxial cold pressing process and sintering under argon protective atmosphere. Microstructural analysis was performed for both as-pressed compacts using light microscopy. Additionally, computed tomography studies were carried out, in order to examine the internal structure of compacts. Chosen mechanical properties, such as Vickers hardness and compression strength was also determined and compared. The conducted research proves that the proposed production method leads to obtain materials with no structural defects and relatively low porosity. Moreover, due to the proper selection of manufacturing parameters, favorable microstructures can be received, as well as mechanical properties, which are comparable to conventionally produced material with the corresponding chemical composition.

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Authors and Affiliations

K. Zyguła
ORCID: ORCID
M. Wojtaszek
ORCID: ORCID
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Abstract

A novel compact Ultra-Wide-Band Planar Inverted- L antenna is presented and investigated in this paper. The proposed antenna consists of a square planar radiating element with a U-shaped slot. The radiating element is supported by a shorting wall, and fed by a single 50 Ohms characteristic impedance microstripe line, printed on the top of the FR-4 substrate. The ground plane of the antenna is printed on the other side of the substrate. The entire antenna occupies only a small volume of 20mm × 35mm × 4mm, and is capable of operating from 4.2GHz to 8.6GHz (68.75%) and offers a maximum gain of 5.24dB. Therefore, it is suitable for UWB systems and other wireless and mobile technologies and, thus, can be integrated into smartwatch, mobile phones, tablets and laptops. The design of this antenna was carried out using 3D software such as CST studio and Ansoft HFSS to compare and validate the results.
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Authors and Affiliations

Iman Ben Issa
1
Mohamed Essaaidi
2

  1. Department of Physics, Abdelmalek Essaadi University, Faculty of Science, Tetuan, Morocco
  2. High National School for Computer Scienceand Systems Analysis- Rabat, Mohammed V University, Rabat, Morocco
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Abstract

This paper deals with the implementation of a DC and AC double-gate MOSFET compact model in the Verilog- AMS language for the transient simulation and the configuration of ultra low-power analog circuits. The Verilog-AMS description of the proposed model is inserted in SMASH circuit simulator for the transient simulation and the configuration of the Colpitts oscillator, the common-source amplifier, and the inverter. The proposed model has the advantages of being simple and compact. It was validated using TCAD simulation results of the same transistor realized with Silvaco Software.
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Bibliography

[1] N. Arora, “MOSFET Modeling for VLSl Circuit Simulation: Theory and Practice,” World Scientific, 1993.
[2] International Technology Roadmap for Semiconductors. Available: http://www.itrs2.net, 2017.
[3] O. Samy, H. Abdelhamid, Y. Ismail, A. Zekry, “A 2D compact model for lightly doped DGMOSFETs (P-DGFETs) including negative bias temperature instability (NBTI) and short channel effects (SCEs),” Microelectronics reliability, 2016, 67, 82-88.
[4] J-P. Colinge, “FinFETs and Other Multi-Gate Transistors,” Springer, 2008.
[5] A. Amara, “Planar Double-Gate Transistor, From Technology to Circuit,” Springer, 2009.
[6] D. Stefanović, M. Kayal, M, “Structured Analog CMOS Design,” Springer, 2008.
[7] A. Mangla, M.-A. Chalkiadaki, F. Fadhuile, T. Taris, Y. Deval, C. C. Enz, “Design methodology for ultra low-power analog circuits using next generation BSIM6 MOSFET compact model,” Microelectronics journal, 2013, 44, 570-575.
[8] A.B. Bhattacharyya, “Compact MOSFET models for VLSI design,” Wiley, 2009.
[9] B. Smaani, S. Latreche, B. Iñiguez, „Compact drain-current model for undoped cylindrical surrounding-gate MOSFETs including short channel effects,” J. Appl. Phys., 2013, 114.
[10] J-M. Sallese, F. Krummenacher, F. Prégaldiny, „A design oriented charge-based current model for symmetric DG MOSFET and its correlation with the EKV formalism,” Solid-State Electronics, 2012, 49, 485-489.
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[13] O. Cobianu, M. Soffke, A. Glesner, “Verilog-A model of an undoped symmetric dual-gate MOSFET,” Int. Adv. Radio Sci, 2006, 4, 303–306.
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[17] O. Samy, H. Abdelhamid , Y. Ismail, A. Zekry, “A 2D compact model for lightly doped DG MOSFETs (P-DGFETs) including negative bias temperature instability (NBTI) and short channel effects (SCEs),” Microelectronics Reliability, 2016, 67, 82-88.
[18] Y. Taur, X. Liang, “A continuous, analytic drain-current model for DG MOSFETs,” IEEE Electron device Letters, 2004, 25, 2, 107–109.
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[24] A.Rana1, P. Gaikwad, “Colpitts oscillator: design and performance optimization,” Int. Journal of Applied Sciences and Engineering Research, 2014, 3, 913–919.
[25] SMASH User Manual Version 5.18 Release, 2012.
[26] Device simulator ATLAS, Silvaco International, 2007.
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Authors and Affiliations

Billel Smaani
1
Yacin Meraihi
2
Fares Nafa
2
Mohamed Salah Benlatreche
3
Hamza Akroum
4
Saida Latreche
5

  1. Ingénierie des Systémes Electriques Department, Faculty of Technology, Boumerdes University, Algeria
  2. Laboratoire d'Ingénierie et Systèmes de Télécommunications, Faculté de Technologie, Boumerdes, Algeria
  3. Centre Universitaire Abdel Hafid Boussouf Mila, Algeria
  4. Laboratoire d’Automatique Appliquée, Université M’Hamed Bougara de Boumerdes, Algeria
  5. Laboratoire Hyperfréquences et Semiconducteurs, Electronique Department, Constantine 1 University, Algeria
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Abstract

Sand Casting process depends mainly on properties of the green sand mould, sand casting requires requires producing green sand mould without failure and breakage during separation the mould from the model, transportation and handling. Production of the green sand mould corresponding to dimensions and form of the desired model without troubles depends on the properties of the green sand. Ratio of constituents, preparation method of the green sand, mixing and pressing processes determine properties of green sand. In the present work, study effect of the moulding parameters of bentonite content, mixing time, and compactability percentage on the properties of the green sand mould have been investigated. Design of experiments through Taguchi method was used to evaluate properties of permeability, compressive strength, and tensile strength of the green sand. It was found that 47% of compactability, 9(min) of mixing time, and 6% of bentonite content gives highest values of these properties simultaneously.
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Authors and Affiliations

Dheya Abdulamer
1
ORCID: ORCID

  1. University of Technology, Iraq
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Abstract

Compacted Graphite Iron (CGI), is a unique casting material characterized by its graphite form and extensive matrix contact surface. This type of cast iron has a tendency towards direct ferritization and possesses a complex set of intriguing properties. The use of data mining methods in modern foundry material development facilitates the achievement of improved product quality parameters. When designing a new product, it is always necessary to have a comprehensive understanding of the influence of alloying elements on the microstructure and consequently on the properties of the analyzed material. Empirical studies allow for a qualitative assessment of the above-mentioned relationships, but it is the use of intelligent computational techniques that allows for the construction of an approximate model of the microstructure and, consequently, precise predictions. The formulated prognostic model supports technological decisions during the casting design phase and is considered as the first step in the selection of the appropriate material type.
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Bibliography

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Authors and Affiliations

Łukasz Sztangret
1
ORCID: ORCID
Izabela Olejarczyk-Wożeńska
1
ORCID: ORCID
Krzysztof Regulski
1
ORCID: ORCID
Grzegorz Gumienny
2
ORCID: ORCID
Barbara Mrzygłód
1
ORCID: ORCID

  1. AGH University of Science and Technology, Poland
  2. Lodz University of Technology, Poland
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Abstract

A statistical approach was conducted to investigate effect of independent factors of the mixing time compactability and bentonite percentage on dependent variables of permeability, compression and tensile strength of sand mould properties. Using statistical method save time in estimating the dependent variables that affect the moulding properties of green sand and the optimal levels of each factor that produce the desired results.
The results yielded indicate that there are variations in the effects of these factors and their interactions on different properties of green sand. The outcomes obtained a range of permeability values, with the highest and lowest numbers being 125 and 84. The sand exhibited high values of tensile and compressive strength measuring at 0.33N/cm2 and 17.67N/cm2. Conversely it demonstrated low levels of tensile and compressive strength reaching 0.14N/cm2 and 9.32N/cm2.
These results suggest that the moulding factors and their interactions have an important role in determining properties of the green sand. ANOVA was used to assess effect of various factors on different properties of the green sand. The results obtained suggest that compactability factor play a significant effect on permeability, the mixing time or bentonite factor has a significant effect on the compressive strength and mixing time or compactability factor has a significant impact on the tensile strength with a significance level lower than 5%. It is found that neither the mixing time nor the amount of bentonite used in the green sand mix has a significant impact on its permeability. Compactability of the green sand does not has a significant effect on the compressive strength. Bentonite used in green sand mix does not have a significant impact on its tensile strength.
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Authors and Affiliations

Dheya Abdulamer
1
ORCID: ORCID

  1. University of Technology, Iraq
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Abstract

The paper presents the effect of tin on the crystallization process, microstructure and hardness of cast iron with compacted (vermicular) graphite. The compacted graphite was obtained with the use of magnesium treatment process (Inmold technology). The lack of significant effect of tin on the temperature of the eutectic transformation has been demonstrated. On the other hand, a significant decrease in the eutectoid transformation temperature with increasing tin concentration has been shown. It was demonstrated that tin narrows the temperature range of the austenite transformation. The effect of tin on the microstructure of cast iron with compacted graphite considering casting wall thickness has been investigated and described. The carbide-forming effect of tin in thin-walled (3 mm) castings has been demonstrated. The nomograms describing the microstructure of compacted graphite iron versus tin concentration have been developed. The effect of tin on the hardness of cast iron was given.

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Authors and Affiliations

Grzegorz Gumienny
ORCID: ORCID
B. Kurowska
ORCID: ORCID
P. Fabian
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Abstract

The objective of the present research is to develop new admixed lubricants which can be used for high-density sintered iron when processed using warm die and warm compaction. Depending on various lubricants, the effect of compaction temperature on the ejection behavior and sintered properties was studied. Lubricants were prepared by mixing of Zn-stearate and ethylene bis stearamide (EBS) in various compositions. The iron powders blended with lubricants were compacted under the pressure of 700 MPa at various temperatures. The green compacts were sintered at 1120°C for 30 min. Microstructure, density, hardness, and transverse rupture strength of sintered materials with different lubricants were investigated in detail.
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Authors and Affiliations

Min Chul Oh
1 2
ORCID: ORCID
Byungmin Ahn
1
ORCID: ORCID

  1. Ajou University, Department of Materials Science and Engineering and Department of Energy Systems Research, 206 WORLDCUP-RO, SUWON, Gyeonggi, 16499, Korea
  2. AI & Mechanical System Center, Institute for Advanced Engineering, 175-28 GOAN-RO 51 BEON-GIL, Yyongin, Gyeonggi, 17180, Korea
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Abstract

Self compacting concrete (SCC) filling layer is core structure of China rail track system (CRTS) ? type ballastless track. Construction quality, service performance and durability of CRTS ? ballastless structure are affected by stability of SCC for filling layer. In this study, the stability of SCC of filling layer is researched at three levels as paste, mortar and concrete by theory and experiment. Evaluation indices including bleeding (��), surface bubble rate (��), thickness of paste (��paste) and thickness of surface mortar (��) are proposed based on the theoretical calculation and analysis. The threshold viscosity of paste 0.394 Pa·s and mixture satisfied area are obtained at paste level based on the relationship between viscosity and ��, �� of paste. The mixture satisfied area was defined at mortar level under criterions of maximum value of ��paste and slump flow. Optimal range of gap between neighboring aggregates (��ca) 12.4 mm~14.1 mm is chosen by flow ability, passing ability, stable ability of SCC. These research results will help to further understand the stability of SCC.
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Authors and Affiliations

He Liu
1
ORCID: ORCID
Jingyi Zhang
2
ORCID: ORCID
Yanhai Yang
1
ORCID: ORCID

  1. Shenyang Jianzhu University, School of Transportation and Geometics Engineering, No. 25 Hunnan Zhong Road, Hunnan District, 110168 Shenyang, China
  2. Shenyang Urban Construction University, School of Civil Engineering, No.380 Bai Ta Road, Hunnan District, 110167 Shenyang, China

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