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Papers by Michaela Gkantou

IOP Conference Series: Materials Science and Engineering, 2021

Manganese (Mn) is expected in the majority of freshwater sources due to the wide usage of this el... more Manganese (Mn) is expected in the majority of freshwater sources due to the wide usage of this element in many industries, such as steel and battery industries, where its concentration in some water bodies could exceed 9600 μg/L. High concentrations of Mn cause many diseases such as Parkinsonism, and lung diseases. The present investigation explores an electrocoagulation unit to remove manganese from water. The electrodes of the electrocoagulation unit are made from iron and aluminium (iron anode, and aluminium cathode). This cell is employed to remediate water samples with 2000 μg/L of manganese. The impacts of many different operating factors, specifically the initial pHs, electric currents, and distances between electrodes, on manganese removals was tested to attend the best performance of manganese removal. The central composite method was applied for the optimization of the operating conditions. Additionally, the estimated power consumption was calculated under the optimum cond...

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska, 2021

The increased use of reactive powder concrete (RPC) in concrete structures has attracted attentio... more The increased use of reactive powder concrete (RPC) in concrete structures has attracted attention towards the structural behavior of RPC in fires. This work examines experimentally the performance of RPC and NSC columns subjected to 25% of the ultimate load and exposed to direct fire flame for a period of 30 and 60 min at various temperature levels. The paper aims to evaluate the maximum temperature level and fire duration that can be withstood by this type of concrete columns. The results show that the failure mode of RPC columns without reinforcement is a sudden shear failure, whereas the failure mode of reinforced RPC columns is a crushing failure with rupture of certain ties. The RPC columns at high temperatures spall intensively; additionally, the ultimate strength clearly decreases compared to the NSC columns at the same conditions.

IOP Conference Series: Materials Science and Engineering, 2021

Preserving the temperature of the indoor environment within the acceptable limits during the cold... more Preserving the temperature of the indoor environment within the acceptable limits during the cold weather using a minimal amount of energy consumption is an important factor in the modern housing systems and green buildings. Therefore, this study aims to provide eco-friendly insulation material (organic material). The utlised organic material in this study was Lignocellusic Biomass (it is also known as Poaceae common reed, and Phragmites australis) and straw. The insulation efficiency of this organic matter was evaluated via testing its performance under controlled conditions. The experimental work included three types of insulation, namely organic insulation (straw and reeds), industrial insulation material (fiberglass), and bricks (without insulation). The insulation level was monitored using an infrared camera. The thermal profile was created for each insulation scenario. The results showed that the efficiency of the organic insulation was similar to the fiberglass; only a 0.84% ...

Chemosphere, 2020

The version presented here may differ from the published version or from the version of the recor... more The version presented here may differ from the published version or from the version of the record. Please see the repository URL above for details on accessing the published version and note that access may require a subscription.

Journal of Constructional Steel Research

CivilEng

Research studies have been reported on aluminium alloy tubular and doubly symmetric open cross-se... more Research studies have been reported on aluminium alloy tubular and doubly symmetric open cross-sections, whilst studies on angle cross-sections remain limited. This paper presents a comprehensive numerical study on the response of aluminium alloy angle stub columns. Finite element models are developed following a series of modelling assumptions. Geometrically and materially nonlinear analyses with imperfections included are executed, and the obtained results are validated against experimental data available in the literature. Subsequently, a parametric study is carried out to investigate the local buckling behaviour of aluminium alloy angles. For this purpose, a broad range of cross-sectional aspect ratios, slenderness and two types of structural aluminium alloys are considered. Their effect on the cross-sectional behaviour and strength is discussed. Moreover, the numerically obtained ultimate strengths together with literature test data are utilised to assess the applicability of t...

IOP Conference Series: Materials Science and Engineering

Concrete-filled aluminium tubular (CFAT) columns have numerous benefits, such as aesthetic appear... more Concrete-filled aluminium tubular (CFAT) columns have numerous benefits, such as aesthetic appearance, less self-weight and good corrosion resistance, over conventional concrete-filled tubular columns. A limited body of research exists for CFAT columns, and the research on the behaviour of CFAT columns under eccentric loading is rather rare. Therefore, the present study aims at investigating the eccentric compressive response of CFAT columns by means of numerical analysis. The numerical models were developed considering nonlinear behaviour of the materials. The models were validated against experimental data obtained from concentric compression tests of CFAT columns. The columns used in the experiments were 6082-T6 heat-treated aluminium alloy square tubes filled with 30 MPa cube strength concrete. The validated models were used to study the influence of different loading eccentricities on the behaviour of CFAT columns. The results are discussed in terms of ultimate strengths and lo...

Journal of Physics: Conference Series

Aluminium alloys are characterised by numerous benefits, such as ease of fabrication, good streng... more Aluminium alloys are characterised by numerous benefits, such as ease of fabrication, good strength-to-weight ratio, attractive appearance and high corrosion resistance. On the other hand, aluminium has low Young’s Modulus and as a result, it is susceptible to structural instability phenomena that can subsequently affect the structural integrity. Improved strength and stiffness can be achieved by combining aluminium alloys with concrete. The present work investigates numerically the response of concrete-filled aluminium tubular members under axial compression. In particular, 6082-T6 extruded aluminium alloy rectangular and square hollow sections filled with C30 concrete are examined. Finite element models are developed accounting for geometric and material non-linearities. Upon validation against experimental data, the finite element models are used to conduct a thorough parametric study over a wide range of structural members likely to occur in practice to investigate their structu...

Journal of Physics: Conference Series

Recently, aluminium alloys are extensively used in the construction sector because of their small... more Recently, aluminium alloys are extensively used in the construction sector because of their small self-weight, good corrosion resistance, low maintenance, high recyclability, and aesthetic appearance. However, one of the main disadvantages of these alloys is the low Young’s modulus, which may cause a stability issue of aluminium structural members. Moreover, currently available design standards for predicting buckling resistance of aluminium columns are generally conservative. Therefore, additional research is required to evaluate the actual structural behaviour of aluminium columns under axial compression. The present study experimentally investigated the buckling response of 13 square and rectangular 6082-T6 aluminium alloy columns subjected to axial compression. The properties of the aluminium alloy were achieved from tensile test of coupon samples. The compressive load was employed concentrically by using a knife-edge hinge to ensure pin supports on both ends of the specimens. T...

Lecture Notes in Civil Engineering, 2021

Thin-Walled Structures, 2022

Thin-Walled Structures, 2022

Structures, 2020

Number of figures: 13 Number of tables: 5 Nomenclature Ag Cross sectional area of grout core Ak C... more Number of figures: 13 Number of tables: 5 Nomenclature Ag Cross sectional area of grout core Ak Cross sectional area of hollow part Aso Cross sectional area of outer steel tube Asi Cross sectional area of inner steel tube Do External tube diameter Di Internal tube diameter Dg Grout core diameter f syo External steel yield strength f syi Internal steel yield strength fsy Steel yield strength f rp Lateral confining pressure f gt Grout tensile strength fgc Compressive strength of grout f cu Compressive strength of cubic sample f c Compressive cylinder strength f cc ' Confined compressive strength f c '

IOP Conference Series: Materials Science and Engineering, 2021

The current study numerically investigates the structural behaviour of aluminium alloy square and... more The current study numerically investigates the structural behaviour of aluminium alloy square and rectangular hollow cross-sections under compression and uniaxial bending. Material and geometric nonlinear responses were carefully considered within finite element modelling. Geometric imperfections were also included through the execution of an initial eigenvalue buckling analysis. A thorough parametric study was carried out over a range of width-to-thickness ratios used in practice. Different initial loading eccentricities were examined generating various ratios of compressive axial load and bending moment at failure. The relatively new 6082-T6 heat-treated aluminium alloy, which is increasingly employed in structural applications owing to its high strength, was selected for this study. Based on the obtained numerical capacities, the EN 1999-1-1 design interaction curves were assessed providing rather conservative predictions, particularly for the stockiest cross-sections. The simpli...

Journal of Constructional Steel Research, 2021

The version presented here may differ from the published version or from the version of the recor... more The version presented here may differ from the published version or from the version of the record. Please see the repository URL above for details on accessing the published version and note that access may require a subscription.

IOP Conference Series: Materials Science and Engineering, 2021

Manganese (Mn) is expected in the majority of freshwater sources due to the wide usage of this el... more Manganese (Mn) is expected in the majority of freshwater sources due to the wide usage of this element in many industries, such as steel and battery industries, where its concentration in some water bodies could exceed 9600 μg/L. High concentrations of Mn cause many diseases such as Parkinsonism, and lung diseases. The present investigation explores an electrocoagulation unit to remove manganese from water. The electrodes of the electrocoagulation unit are made from iron and aluminium (iron anode, and aluminium cathode). This cell is employed to remediate water samples with 2000 μg/L of manganese. The impacts of many different operating factors, specifically the initial pHs, electric currents, and distances between electrodes, on manganese removals was tested to attend the best performance of manganese removal. The central composite method was applied for the optimization of the operating conditions. Additionally, the estimated power consumption was calculated under the optimum cond...

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska, 2021

The increased use of reactive powder concrete (RPC) in concrete structures has attracted attentio... more The increased use of reactive powder concrete (RPC) in concrete structures has attracted attention towards the structural behavior of RPC in fires. This work examines experimentally the performance of RPC and NSC columns subjected to 25% of the ultimate load and exposed to direct fire flame for a period of 30 and 60 min at various temperature levels. The paper aims to evaluate the maximum temperature level and fire duration that can be withstood by this type of concrete columns. The results show that the failure mode of RPC columns without reinforcement is a sudden shear failure, whereas the failure mode of reinforced RPC columns is a crushing failure with rupture of certain ties. The RPC columns at high temperatures spall intensively; additionally, the ultimate strength clearly decreases compared to the NSC columns at the same conditions.

IOP Conference Series: Materials Science and Engineering, 2021

Preserving the temperature of the indoor environment within the acceptable limits during the cold... more Preserving the temperature of the indoor environment within the acceptable limits during the cold weather using a minimal amount of energy consumption is an important factor in the modern housing systems and green buildings. Therefore, this study aims to provide eco-friendly insulation material (organic material). The utlised organic material in this study was Lignocellusic Biomass (it is also known as Poaceae common reed, and Phragmites australis) and straw. The insulation efficiency of this organic matter was evaluated via testing its performance under controlled conditions. The experimental work included three types of insulation, namely organic insulation (straw and reeds), industrial insulation material (fiberglass), and bricks (without insulation). The insulation level was monitored using an infrared camera. The thermal profile was created for each insulation scenario. The results showed that the efficiency of the organic insulation was similar to the fiberglass; only a 0.84% ...

Chemosphere, 2020

The version presented here may differ from the published version or from the version of the recor... more The version presented here may differ from the published version or from the version of the record. Please see the repository URL above for details on accessing the published version and note that access may require a subscription.

Journal of Constructional Steel Research

CivilEng

Research studies have been reported on aluminium alloy tubular and doubly symmetric open cross-se... more Research studies have been reported on aluminium alloy tubular and doubly symmetric open cross-sections, whilst studies on angle cross-sections remain limited. This paper presents a comprehensive numerical study on the response of aluminium alloy angle stub columns. Finite element models are developed following a series of modelling assumptions. Geometrically and materially nonlinear analyses with imperfections included are executed, and the obtained results are validated against experimental data available in the literature. Subsequently, a parametric study is carried out to investigate the local buckling behaviour of aluminium alloy angles. For this purpose, a broad range of cross-sectional aspect ratios, slenderness and two types of structural aluminium alloys are considered. Their effect on the cross-sectional behaviour and strength is discussed. Moreover, the numerically obtained ultimate strengths together with literature test data are utilised to assess the applicability of t...

IOP Conference Series: Materials Science and Engineering

Concrete-filled aluminium tubular (CFAT) columns have numerous benefits, such as aesthetic appear... more Concrete-filled aluminium tubular (CFAT) columns have numerous benefits, such as aesthetic appearance, less self-weight and good corrosion resistance, over conventional concrete-filled tubular columns. A limited body of research exists for CFAT columns, and the research on the behaviour of CFAT columns under eccentric loading is rather rare. Therefore, the present study aims at investigating the eccentric compressive response of CFAT columns by means of numerical analysis. The numerical models were developed considering nonlinear behaviour of the materials. The models were validated against experimental data obtained from concentric compression tests of CFAT columns. The columns used in the experiments were 6082-T6 heat-treated aluminium alloy square tubes filled with 30 MPa cube strength concrete. The validated models were used to study the influence of different loading eccentricities on the behaviour of CFAT columns. The results are discussed in terms of ultimate strengths and lo...

Journal of Physics: Conference Series

Aluminium alloys are characterised by numerous benefits, such as ease of fabrication, good streng... more Aluminium alloys are characterised by numerous benefits, such as ease of fabrication, good strength-to-weight ratio, attractive appearance and high corrosion resistance. On the other hand, aluminium has low Young’s Modulus and as a result, it is susceptible to structural instability phenomena that can subsequently affect the structural integrity. Improved strength and stiffness can be achieved by combining aluminium alloys with concrete. The present work investigates numerically the response of concrete-filled aluminium tubular members under axial compression. In particular, 6082-T6 extruded aluminium alloy rectangular and square hollow sections filled with C30 concrete are examined. Finite element models are developed accounting for geometric and material non-linearities. Upon validation against experimental data, the finite element models are used to conduct a thorough parametric study over a wide range of structural members likely to occur in practice to investigate their structu...

Journal of Physics: Conference Series

Recently, aluminium alloys are extensively used in the construction sector because of their small... more Recently, aluminium alloys are extensively used in the construction sector because of their small self-weight, good corrosion resistance, low maintenance, high recyclability, and aesthetic appearance. However, one of the main disadvantages of these alloys is the low Young’s modulus, which may cause a stability issue of aluminium structural members. Moreover, currently available design standards for predicting buckling resistance of aluminium columns are generally conservative. Therefore, additional research is required to evaluate the actual structural behaviour of aluminium columns under axial compression. The present study experimentally investigated the buckling response of 13 square and rectangular 6082-T6 aluminium alloy columns subjected to axial compression. The properties of the aluminium alloy were achieved from tensile test of coupon samples. The compressive load was employed concentrically by using a knife-edge hinge to ensure pin supports on both ends of the specimens. T...

Lecture Notes in Civil Engineering, 2021

Thin-Walled Structures, 2022

Thin-Walled Structures, 2022

Structures, 2020

Number of figures: 13 Number of tables: 5 Nomenclature Ag Cross sectional area of grout core Ak C... more Number of figures: 13 Number of tables: 5 Nomenclature Ag Cross sectional area of grout core Ak Cross sectional area of hollow part Aso Cross sectional area of outer steel tube Asi Cross sectional area of inner steel tube Do External tube diameter Di Internal tube diameter Dg Grout core diameter f syo External steel yield strength f syi Internal steel yield strength fsy Steel yield strength f rp Lateral confining pressure f gt Grout tensile strength fgc Compressive strength of grout f cu Compressive strength of cubic sample f c Compressive cylinder strength f cc ' Confined compressive strength f c '

IOP Conference Series: Materials Science and Engineering, 2021

The current study numerically investigates the structural behaviour of aluminium alloy square and... more The current study numerically investigates the structural behaviour of aluminium alloy square and rectangular hollow cross-sections under compression and uniaxial bending. Material and geometric nonlinear responses were carefully considered within finite element modelling. Geometric imperfections were also included through the execution of an initial eigenvalue buckling analysis. A thorough parametric study was carried out over a range of width-to-thickness ratios used in practice. Different initial loading eccentricities were examined generating various ratios of compressive axial load and bending moment at failure. The relatively new 6082-T6 heat-treated aluminium alloy, which is increasingly employed in structural applications owing to its high strength, was selected for this study. Based on the obtained numerical capacities, the EN 1999-1-1 design interaction curves were assessed providing rather conservative predictions, particularly for the stockiest cross-sections. The simpli...

Journal of Constructional Steel Research, 2021

The version presented here may differ from the published version or from the version of the recor... more The version presented here may differ from the published version or from the version of the record. Please see the repository URL above for details on accessing the published version and note that access may require a subscription.