Magazine et Edition

Volume 5 (2022): Edition 2 (October 2022)

Volume 5 (2022): Edition 1 (April 2022)

Volume 4 (2021): Edition 2 (October 2021)

Volume 4 (2021): Edition 1 (April 2021)

Volume 3 (2020): Edition 2 (October 2020)

Volume 3 (2020): Edition 1 (April 2020)

Volume 2 (2019): Edition 2 (October 2019)

Volume 2 (2019): Edition 1 (April 2019)

Volume 1 (2018): Edition 2 (October 2018)

Volume 1 (2018): Edition 1 (April 2018)

Détails du magazine
Format
Magazine
eISSN
2601-8799
Première publication
30 Jan 2019
Période de publication
2 fois par an
Langues
Anglais

Chercher

Volume 5 (2022): Edition 1 (April 2022)

Détails du magazine
Format
Magazine
eISSN
2601-8799
Première publication
30 Jan 2019
Période de publication
2 fois par an
Langues
Anglais

Chercher

10 Articles
Accès libre

Simulation of CuE Copper Alloy in a Closed-Die Multi-Axial Forging Tool

Publié en ligne: 20 Jul 2022
Pages: 1 - 5

Résumé

Abstract

Two-way multi-axial forging was performed on a newly designed closed-die forging tool. The tool was operated on an MTS 810 material testing system. The connected computer recorded force and crosshead displacement as a function of time during operation. The sample material of the four-step forging experiment was CuE copper alloy. The plastic deformation was 0.8 per step, thus the rate of cumulative equivalent plastic strain was 3.2 by the end of the process. The speed of movement of the active tools during the whole test was 2 mm/min. Finite element simulation was performed with QForm3D software to investigate the force conditions of the process. The necessary flow curve was determined by Watts-Ford test. The force-displacement curves of the physical simulation were compared with the results of the finite element modeling.

Mots clés

  • multi-axial forging
  • finite element modeling
  • Watts-Ford test
Accès libre

Estimation of Dislocation Distribution at Mid Thickness for 1050 Al

Publié en ligne: 20 Jul 2022
Pages: 6 - 9

Résumé

Abstract

The current study reports three different techniques to estimate the distribution of dislocation density at the mid thickness of 1050 Al alloy. It is well known that the strain distribution is inhomogeneous through the thickness of rolled materials, which affects the evolution of dislocation density during the process of deformation. In this study, the number of dislocations was calculated experimentally using indentation technique in 46.8% cold rolled 1050 Al sheet and the result was verified by two numerical methods.

Mots clés

  • dislocation density
  • microhardness
  • numerical models
Accès libre

Laser Cutting of Brass Sheet

Publié en ligne: 20 Jul 2022
Pages: 10 - 13

Résumé

Abstract

Laser cutting of copper-based alloy sheets is very difficult due to their high reflectivity, which can be modified with graphitization. The optimal parameters for a 2.5 mm thick brass sheet were determined by examining the laser beam parameter variations and the laser cut kerfs. The best characteristics of kerfs were obtained when the surface was graphitized, the laser frequency was 200 Hz, the applied laser speed was 1400mm/min on 2500 W power and the focal point was under the surface by 0.8 mm. The applied working gas was nitrogen.

Mots clés

  • copper alloy sheet
  • CO2 laser
  • cutting speed
  • frequency
  • graphite
  • kerf
Accès libre

Selection Method of Flow Modifier Polymers for Chemical Enhanced Oil Recovery

Publié en ligne: 20 Jul 2022
Pages: 14 - 17

Résumé

Abstract

Chemically enhanced oil recovery methods can provide a solution to increase oil recovery. Of these, surfactant- polymer flooding is common. Efficient selection of polymers and surfactants is essential for a successful EOR project. Detailed selection of polymers is a lengthy task that involves a number of studies. Our goal is to create a fast polymer selection method based on which the most promising polymer can be selected.

Mots clés

  • polymer selection
  • dynamic viscosity
  • hydrodynamic diameter
  • enhanced oil recovery
Accès libre

Reinforced Matrix Syntactic Foams Filled with Ceramic Hollow Spheres

Publié en ligne: 20 Jul 2022
Pages: 18 - 22

Résumé

Abstract

Metal matrix syntactic foams are cellular materials in which the matrix is metal and within that matrix are non-metallic cells formed by filler material. These materials have low density, and besides that, they have high compressive strength and energy absorption. The main goal was to improve these properties by reinforcing the matrix with ceramic grains. During the experiment, molten A356 aluminium (7Si-0,3Mg) was infiltrated between the mixture of the filler and the reinforcement material. The specimens were produced with low-pressure infiltration. Different reinforcement materials were used: aluminium-oxide with three different grain sizes and colour designations and one type of silicon carbide. After heat-treatment, standardised compression tests were executed on the specimens. The results were compared to the results of the non-reinforced samples.

Mots clés

  • syntactic metal foam
  • reinforcement in matrix material
  • compression test
Accès libre

Investigation of the Application of Coagulants in Case of Domestic Greywater Fraction

Publié en ligne: 20 Jul 2022
Pages: 23 - 28

Résumé

Abstract

During our research work, we examined the removal of contaminants from synthetically produced bathing waters using different coagulants and studied the efficiency and the mechanism of coagulation-flocculation processes in detail. In our work, we performed experiments with two different types of coagulants (iron(III) chloride and polyelectrolyte) and compared their efficiencies. The zeta potential and its change were monitored as a qualifying parameter while other water quality parameters were also analyzed. In our experiments, a newly acquired flocculator device was also used to study the coagulation-flocculation processes of larger volume samples. The main goal of our research is to promote the sustainable management of drinking water quality and to study the bathing water reuse possibilities.

Mots clés

  • synthetic greywater
  • iron(III) chloride
  • polyelectrolyte
  • reuse
Accès libre

Investigation of the Effect of Over-Etching During Color Etching

Publié en ligne: 20 Jul 2022
Pages: 29 - 34

Résumé

Abstract

During color etching, the examined grain structure undergoes a continuous, cyclic color change. This phenomenon is accompanied by a continuous loss of light intensity reflected from the surface. If the etching process is not stopped in time, the surface will be over etched. As a result, the separability of the individual grains will be greatly damaged, which can lead to a significant loss of information. It was investigated how to determine the moment of over-etching for each grain. During the in-situ observation of the etching, the time at which a particle can be considered over etched was determined by measuring the luminance normalized to the initial state.

Mots clés

  • color etching
  • metallography
  • Beraha I
  • microscopy
  • luminance
  • intensity
  • in-situ
  • steel
Accès libre

High Heat Input Welding of NSSC 2120 Type Lean Duplex Steel

Publié en ligne: 20 Jul 2022
Pages: 35 - 38

Résumé

Abstract

Duplex stainless steels offer a high strength alternative to stainless steel, while providing excellent corrosion resistance, due to their dual-phase microstructure. This microstructure can be significantly influenced during welding, thus the maximum recommended heat input is usually 2.5 kJ/mm. In this research, we inspected the high heat input (3 kJ/mm) weldability of NSSC 2120 lean duplex stainless steel, which is designed and developed specifically for this purpose. The welds were evaluated by metallographic techniques and corrosion tests. It was found the NSSC 2120 grade can be welded with high heat input without deterioration in the phase balance and microstructure.

Mots clés

  • lean duplex stainless steel
  • electrochemical etching
  • microstructure
Accès libre

Development of a Novel Hybrid Manufacturing Technology For Continuous Fiber-Reinforced Thermo-Plastic Composites

Publié en ligne: 20 Jul 2022
Pages: 39 - 44

Résumé

Abstract

In this study, we present a novel approach for the production of continuous fiber-reinforced thermoplastic composites by combining injection molding and additive manufacturing. After exploring the design requirements, we manufactured inserts via continuous fiber-reinforced 3D printing, then we used them as reinforcement for injection-molded samples. Improper fiber placement can cause warpage as the continuous fibers prevent shrinking; however, warpage can be compensated with the insert geometry. The reinforcement resulted in an increase of about 30% in the properties tested.

Mots clés

  • additive manufacturing
  • injection molding
  • fiber-reinforced polymer composite
Accès libre

Analysis of Thermogravimetric and Dynamic Mechanical Properties of PLA/PBS Blends Doped With Zinc Oxide Nanoparticles

Publié en ligne: 20 Jul 2022
Pages: 45 - 51

Résumé

Abstract

In the present work, PLA-PBS blends of 80/20 weight ratio were doped with zinc oxide (2.5; 5; 7.5 and 10 phr) and the flow, thermogravimetric and thermomechanical behaviour of the resulting blends were investigated. Using capillary plasstometry, thermogravimetry (TGA) and dynamic mechanical analysis (DMA), it was found that the increase in zinc oxide content resulted in an increase in the flow indices (MFI, MVR), as well as in the storage and loss modulus values, and a decrease in the thermal stability and glass transition temperature.

Mots clés

  • PLA
  • blends
  • zinc-Oxide
  • thermogravimetry
10 Articles
Accès libre

Simulation of CuE Copper Alloy in a Closed-Die Multi-Axial Forging Tool

Publié en ligne: 20 Jul 2022
Pages: 1 - 5

Résumé

Abstract

Two-way multi-axial forging was performed on a newly designed closed-die forging tool. The tool was operated on an MTS 810 material testing system. The connected computer recorded force and crosshead displacement as a function of time during operation. The sample material of the four-step forging experiment was CuE copper alloy. The plastic deformation was 0.8 per step, thus the rate of cumulative equivalent plastic strain was 3.2 by the end of the process. The speed of movement of the active tools during the whole test was 2 mm/min. Finite element simulation was performed with QForm3D software to investigate the force conditions of the process. The necessary flow curve was determined by Watts-Ford test. The force-displacement curves of the physical simulation were compared with the results of the finite element modeling.

Mots clés

  • multi-axial forging
  • finite element modeling
  • Watts-Ford test
Accès libre

Estimation of Dislocation Distribution at Mid Thickness for 1050 Al

Publié en ligne: 20 Jul 2022
Pages: 6 - 9

Résumé

Abstract

The current study reports three different techniques to estimate the distribution of dislocation density at the mid thickness of 1050 Al alloy. It is well known that the strain distribution is inhomogeneous through the thickness of rolled materials, which affects the evolution of dislocation density during the process of deformation. In this study, the number of dislocations was calculated experimentally using indentation technique in 46.8% cold rolled 1050 Al sheet and the result was verified by two numerical methods.

Mots clés

  • dislocation density
  • microhardness
  • numerical models
Accès libre

Laser Cutting of Brass Sheet

Publié en ligne: 20 Jul 2022
Pages: 10 - 13

Résumé

Abstract

Laser cutting of copper-based alloy sheets is very difficult due to their high reflectivity, which can be modified with graphitization. The optimal parameters for a 2.5 mm thick brass sheet were determined by examining the laser beam parameter variations and the laser cut kerfs. The best characteristics of kerfs were obtained when the surface was graphitized, the laser frequency was 200 Hz, the applied laser speed was 1400mm/min on 2500 W power and the focal point was under the surface by 0.8 mm. The applied working gas was nitrogen.

Mots clés

  • copper alloy sheet
  • CO2 laser
  • cutting speed
  • frequency
  • graphite
  • kerf
Accès libre

Selection Method of Flow Modifier Polymers for Chemical Enhanced Oil Recovery

Publié en ligne: 20 Jul 2022
Pages: 14 - 17

Résumé

Abstract

Chemically enhanced oil recovery methods can provide a solution to increase oil recovery. Of these, surfactant- polymer flooding is common. Efficient selection of polymers and surfactants is essential for a successful EOR project. Detailed selection of polymers is a lengthy task that involves a number of studies. Our goal is to create a fast polymer selection method based on which the most promising polymer can be selected.

Mots clés

  • polymer selection
  • dynamic viscosity
  • hydrodynamic diameter
  • enhanced oil recovery
Accès libre

Reinforced Matrix Syntactic Foams Filled with Ceramic Hollow Spheres

Publié en ligne: 20 Jul 2022
Pages: 18 - 22

Résumé

Abstract

Metal matrix syntactic foams are cellular materials in which the matrix is metal and within that matrix are non-metallic cells formed by filler material. These materials have low density, and besides that, they have high compressive strength and energy absorption. The main goal was to improve these properties by reinforcing the matrix with ceramic grains. During the experiment, molten A356 aluminium (7Si-0,3Mg) was infiltrated between the mixture of the filler and the reinforcement material. The specimens were produced with low-pressure infiltration. Different reinforcement materials were used: aluminium-oxide with three different grain sizes and colour designations and one type of silicon carbide. After heat-treatment, standardised compression tests were executed on the specimens. The results were compared to the results of the non-reinforced samples.

Mots clés

  • syntactic metal foam
  • reinforcement in matrix material
  • compression test
Accès libre

Investigation of the Application of Coagulants in Case of Domestic Greywater Fraction

Publié en ligne: 20 Jul 2022
Pages: 23 - 28

Résumé

Abstract

During our research work, we examined the removal of contaminants from synthetically produced bathing waters using different coagulants and studied the efficiency and the mechanism of coagulation-flocculation processes in detail. In our work, we performed experiments with two different types of coagulants (iron(III) chloride and polyelectrolyte) and compared their efficiencies. The zeta potential and its change were monitored as a qualifying parameter while other water quality parameters were also analyzed. In our experiments, a newly acquired flocculator device was also used to study the coagulation-flocculation processes of larger volume samples. The main goal of our research is to promote the sustainable management of drinking water quality and to study the bathing water reuse possibilities.

Mots clés

  • synthetic greywater
  • iron(III) chloride
  • polyelectrolyte
  • reuse
Accès libre

Investigation of the Effect of Over-Etching During Color Etching

Publié en ligne: 20 Jul 2022
Pages: 29 - 34

Résumé

Abstract

During color etching, the examined grain structure undergoes a continuous, cyclic color change. This phenomenon is accompanied by a continuous loss of light intensity reflected from the surface. If the etching process is not stopped in time, the surface will be over etched. As a result, the separability of the individual grains will be greatly damaged, which can lead to a significant loss of information. It was investigated how to determine the moment of over-etching for each grain. During the in-situ observation of the etching, the time at which a particle can be considered over etched was determined by measuring the luminance normalized to the initial state.

Mots clés

  • color etching
  • metallography
  • Beraha I
  • microscopy
  • luminance
  • intensity
  • in-situ
  • steel
Accès libre

High Heat Input Welding of NSSC 2120 Type Lean Duplex Steel

Publié en ligne: 20 Jul 2022
Pages: 35 - 38

Résumé

Abstract

Duplex stainless steels offer a high strength alternative to stainless steel, while providing excellent corrosion resistance, due to their dual-phase microstructure. This microstructure can be significantly influenced during welding, thus the maximum recommended heat input is usually 2.5 kJ/mm. In this research, we inspected the high heat input (3 kJ/mm) weldability of NSSC 2120 lean duplex stainless steel, which is designed and developed specifically for this purpose. The welds were evaluated by metallographic techniques and corrosion tests. It was found the NSSC 2120 grade can be welded with high heat input without deterioration in the phase balance and microstructure.

Mots clés

  • lean duplex stainless steel
  • electrochemical etching
  • microstructure
Accès libre

Development of a Novel Hybrid Manufacturing Technology For Continuous Fiber-Reinforced Thermo-Plastic Composites

Publié en ligne: 20 Jul 2022
Pages: 39 - 44

Résumé

Abstract

In this study, we present a novel approach for the production of continuous fiber-reinforced thermoplastic composites by combining injection molding and additive manufacturing. After exploring the design requirements, we manufactured inserts via continuous fiber-reinforced 3D printing, then we used them as reinforcement for injection-molded samples. Improper fiber placement can cause warpage as the continuous fibers prevent shrinking; however, warpage can be compensated with the insert geometry. The reinforcement resulted in an increase of about 30% in the properties tested.

Mots clés

  • additive manufacturing
  • injection molding
  • fiber-reinforced polymer composite
Accès libre

Analysis of Thermogravimetric and Dynamic Mechanical Properties of PLA/PBS Blends Doped With Zinc Oxide Nanoparticles

Publié en ligne: 20 Jul 2022
Pages: 45 - 51

Résumé

Abstract

In the present work, PLA-PBS blends of 80/20 weight ratio were doped with zinc oxide (2.5; 5; 7.5 and 10 phr) and the flow, thermogravimetric and thermomechanical behaviour of the resulting blends were investigated. Using capillary plasstometry, thermogravimetry (TGA) and dynamic mechanical analysis (DMA), it was found that the increase in zinc oxide content resulted in an increase in the flow indices (MFI, MVR), as well as in the storage and loss modulus values, and a decrease in the thermal stability and glass transition temperature.

Mots clés

  • PLA
  • blends
  • zinc-Oxide
  • thermogravimetry

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