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Papers by Subhash Mojumdar

Research paper thumbnail of Preparation and properties of Mg (II) complexes with halogenacetic acids, N, N-diethylnicotinamide and aspirin

Research paper thumbnail of Hydration of portland cement, natural zeolite mortar in water and sulphate solution

Materiales de Construcción, 2003

Research paper thumbnail of 20th CTAS Annual Workshop and Exhibition

Journal of Thermal Analysis and Calorimetry, 2011

Research paper thumbnail of Investigation of natural rubber composites with addition of montmorillonite fillers using thermal analysis

Journal of Thermal Analysis and Calorimetry, 2011

This paper is devoted to the investigation of the properties of the natural rubber composites pre... more This paper is devoted to the investigation of the properties of the natural rubber composites prepared using the cation exchanged-montmorillonite fillers. The characteristics of the montmorillonite fillers were studied by Fourier transform infrared spectroscopy (FTIR) and thermogravimetry (TG). These characterized fillers were used to preparation of the natural rubber composites, which were submitted to measurements of dynamic-mechanical thermal analysis (DMTA)

Research paper thumbnail of Effect of anthracene doping on potassium hydrogen phthalate crystals

Journal of Thermal Analysis and Calorimetry, 2010

Research paper thumbnail of TG–DTA, UV and FTIR spectroscopic studies of urea–thiourea mixed crystal

Journal of Thermal Analysis and Calorimetry, 2010

Research paper thumbnail of Performance of Sulphoaluminate-Belite Cement with High C4A3S Content

Sulphoaluminate - belite (SAB) cements are an attractive class of low energy cements from the vie... more Sulphoaluminate - belite (SAB) cements are an attractive class of low energy cements from the viewpoint of energy saving and less CO 2 releasing into the atmosphere during their production. Their hydraulic activity, however, does not match that of the Ordinary Portland cement (PC) and needs improvement before they can be used on their own. Performance of SAB cement with 50.3 wt. % of C 2 S, 20.2 wt. % of C 4 A 3 S, 19.5 wt. % of C 4 AF and 9.7 wt. % of CS has been compared with that of PC having 67.6 wt. % of C 3 S, 5.1 wt. % of C 2 S, 9.2 wt. % of C 3 A, 10.6 wt. % of C 4 AF and 5.9 wt. % of CS, and blast-furnace slag Portland cement (BFSPC) containing 30 wt. % of blast-furnace slag. Mortars with the above cements and siliceous sand with the weight ratio of 1 : 3 and water to cement ratio of 0.5 were manufactured and 40x40x160-mm prisms were stored at 20 °C for 90 days under 100% R.H. - wet air conditions. The physical-mechanical properties (strengths, dynamic modulus of elasticity...

Research paper thumbnail of Phase Compositions and Strengths of One-Year-Old Ternary Cement Composites

Research paper thumbnail of Efecto de la zeolita y de la mezcla zeolita-polvo de hierro en la durabilidad de la suspensión de cemento en agua con dióxido de carbono

La suspension de cemento-bentonita se utiliza con frecuencia para la construccion de muros pantal... more La suspension de cemento-bentonita se utiliza con frecuencia para la construccion de muros pantalla. Su mayor desventaja se halla en la resistencia relativamente baja a los medios liquidos agresivos. La suspension de cemento-bentonita endurecida presenta una importante perdida de peso y de resistencia a compresion conservada en agua saturada con 50 mg de CO2 por litro de solucion. Las probetas se estudian despues de 180 dias de exposicion. Por el contrario, las perdidas de peso y de resistencia a compresion son menores en la suspension de cementozeolita endurecida. Las probetas conservan una estructura rigida incluso despues de 365 dias de ataque con agua de CO2 (carbonica). La resistencia de la suspension de cemento-zeolita se incrementa aun mas con la adicion de polvo de hierro finamente molido. La adicion de zeolita contribuye a la reduccion de la formacion de Ca(OH)2 debido a la reaccion puzolanica de la zeolita, la cual consume el CaO libre y desarrolla una microestructura con ...

Research paper thumbnail of Influence of Portland cement addition to sulphoaluminate - belite cement on hydration and mechanical properties of hardened mortars

Ordinary Portland cement (PC), calcium sulphoaluminate - belite (SAB) cement and a 85 wt. % SAB c... more Ordinary Portland cement (PC), calcium sulphoaluminate - belite (SAB) cement and a 85 wt. % SAB cement/15 wt. % PC blend were used for mortar manufacture (cement to sand weight ratio 1 : 3, w/c ratio 0. 5) of 40×40×160 mm specimens kept in wet air cure (20°C, 100% R.H, for 90 days), and used for the tests. The results reveal the influence of cement type on mortar properties. The mortars, made from tested SAB cement have the worst mechanical properties. The replacement of 15 wt. % of SAB cement by PC contributes to the increase in dynamic modulus of elasticity (DME), flexural strength of the mortar by 15% and compressive strength almost by 40 % compared to the SAB cement mortar. Such mortar behaves mechanically similar to PC mortar. Differences in mechanical properties of mortars are caused by differences in chemical composition of cements (in SAB/PC mortar content of CaO is increased by 6.4 %, contents of Al 2 O 3 and Fe 2 O 3 are decreased by 8.2 % and 7.0%, respectively compared t...

Research paper thumbnail of Prospects of novel macro-defect-free cements for the new millennium

High strength cement-based materials developed recently are being used to explore new application... more High strength cement-based materials developed recently are being used to explore new applications which have not been possible with traditional cement and concrete technology. High flexural strength has not been a property typical of conventional cements, and thus there is no established position for cement technology in many modern industries. The relatively high cost of these materials has limited their uses in civil and architectural applications, which are very common for cements. Searching for new applications in areas currently dominated by metals, plastics and ceramics is a challenging task for cement scientists and engineers. Macrodefect-free (MDF) cement is a polymercement composite at the micrometer and nanometer levels. In these materials the polymer and cement react synergistically to create a unique microstructure with distinct characteristics. MDF cements were first reported [1,2] by the research group of Birchall at Imperial Chemical Industries plc (ICI, United Kingd...

Research paper thumbnail of 20th CTAS Annual Workshop and Exhibition : CTAS 2010 ()

Journal of Thermal Analysis and Calorimetry, 2011

Research paper thumbnail of Special Chapter on current topics at the Canadian Thermal Analysis Society (CTAS)

Journal of Thermal Analysis and Calorimetry, 2014

Research paper thumbnail of Macro-Defect-Free (MDF) Cements with High Moisture Resistance: Chemical, Thermal, SEM and Magnetometric Study

Solid State Phenomena, 2003

Research paper thumbnail of Influence of the material structure on the thermal conductivity of the clothing textiles

Journal of Thermal Analysis and Calorimetry, 2014

Comfort is seen as a comprehensive concept involving the transport of heat, moisture and air in t... more Comfort is seen as a comprehensive concept involving the transport of heat, moisture and air in the fabric of interactions and the human body on the basis of used material, design clothing and other parameters. These transports are slowed down or accelerated. One of the impulses for the detection of comfort is to know the impact of heat transfer, moisture through clothing that is intended to be precisely the objective of activity. Textiles intended for clothing would be reported in some places about the local compression behaviour, resistance to failure and increased transport sweat and moisture. Such clothing should allow ventilation to the outside and dry as quickly as possible, so after some activity remained, thermal resistance prevents the body hypothermia. Textiles are now designed not only to achieve certain properties, but also with respect to such security—sensors, the monitor’s vital functions of the body of the wearer.

Research paper thumbnail of Macrodefect-Free Cements: Chemistry and Impact of the Environment

Key Engineering Materials, 2002

Research paper thumbnail of Degree of hydration in cement paste and C3A-sodium carbonate-water systems

Journal of Thermal Analysis and Calorimetry, 2007

ABSTRACT This research provides a fundamental understanding of the early stage hydration of Portl... more ABSTRACT This research provides a fundamental understanding of the early stage hydration of Portland cement paste, tricalcium aluminate (C3A) paste at water to cement ratio of 0.5 and C3A suspension at water to cement ratio of 5.0 modified by 2 or 4 mass% of sodium carbonate. A high conversion of unreacted clinker minerals to gel-like hydration products in the cement-Na2CO3 pastes takes place rapidly between 1st to 24th h. Contrary the Ca(OH)2 formation within the same time interval is retarded in the excess of CO 32− ions due to intensive rise and growth of CaCO3 crystals in hydrated cement. Later, the conversion of clinker minerals to the hydrate phase is reduced and higher contents of calcite and vaterite relative to that of Ca(OH)2 in comparison with those found in the Portland cement paste are observed. As a consequence a decrease in strength and an increase in porosity between hardened Portland cement paste without sodium carbonate and those modified by Na2CO3 are observed. C3A hydrates very quickly with sodium carbonate between 1st and 24th h forming hydration products rich in bound water and characterized also by complex salts of (x)C3A·(y)CO2·(zH2O type, whereas C3A-H2O system offers C3AH6 as the main hydration product. Higher content of the formed calcium aluminate hydrates in C3A-Na2CO3-H2O system also contributes to early strength increase of Portland cement paste.

Research paper thumbnail of Special Chapter on Current Topics of CTAS2012

Journal of Thermal Analysis and Calorimetry, 2013

Research paper thumbnail of Thermal properties of textile fabrics

Journal of Thermal Analysis and Calorimetry, 2013

ABSTRACT Objective evaluation techniques were used in this study of thermal properties of textile... more ABSTRACT Objective evaluation techniques were used in this study of thermal properties of textile fabric. The Alambeta, P tester, and Togmeter measure the passages of air which were used for evaluation of the physiological properties. Fibrous materials were prepared in the form of textile knitting fabric COOLMAX. It is clear from the measurement that there are considerable differences in the results of measurement with described methods. Device Alambeta is convenient for the measurement and evaluation of various thermal properties. Finally, it can be concluded that this field of measurements is developing and will be the subject of further research of other methods, more suitable for measurement of the various characteristics.

Research paper thumbnail of 17 th Annual Meeting of the Canadian Thermal Analysis Society (CTAS) in conjunction with The 53 rd International Conference on Analytical Sciences and Spectroscopy (ICASS 2007)

Journal of Thermal Analysis and Calorimetry - J THERM ANAL CALORIM, 2008

Research paper thumbnail of Preparation and properties of Mg (II) complexes with halogenacetic acids, N, N-diethylnicotinamide and aspirin

Research paper thumbnail of Hydration of portland cement, natural zeolite mortar in water and sulphate solution

Materiales de Construcción, 2003

Research paper thumbnail of 20th CTAS Annual Workshop and Exhibition

Journal of Thermal Analysis and Calorimetry, 2011

Research paper thumbnail of Investigation of natural rubber composites with addition of montmorillonite fillers using thermal analysis

Journal of Thermal Analysis and Calorimetry, 2011

This paper is devoted to the investigation of the properties of the natural rubber composites pre... more This paper is devoted to the investigation of the properties of the natural rubber composites prepared using the cation exchanged-montmorillonite fillers. The characteristics of the montmorillonite fillers were studied by Fourier transform infrared spectroscopy (FTIR) and thermogravimetry (TG). These characterized fillers were used to preparation of the natural rubber composites, which were submitted to measurements of dynamic-mechanical thermal analysis (DMTA)

Research paper thumbnail of Effect of anthracene doping on potassium hydrogen phthalate crystals

Journal of Thermal Analysis and Calorimetry, 2010

Research paper thumbnail of TG–DTA, UV and FTIR spectroscopic studies of urea–thiourea mixed crystal

Journal of Thermal Analysis and Calorimetry, 2010

Research paper thumbnail of Performance of Sulphoaluminate-Belite Cement with High C4A3S Content

Sulphoaluminate - belite (SAB) cements are an attractive class of low energy cements from the vie... more Sulphoaluminate - belite (SAB) cements are an attractive class of low energy cements from the viewpoint of energy saving and less CO 2 releasing into the atmosphere during their production. Their hydraulic activity, however, does not match that of the Ordinary Portland cement (PC) and needs improvement before they can be used on their own. Performance of SAB cement with 50.3 wt. % of C 2 S, 20.2 wt. % of C 4 A 3 S, 19.5 wt. % of C 4 AF and 9.7 wt. % of CS has been compared with that of PC having 67.6 wt. % of C 3 S, 5.1 wt. % of C 2 S, 9.2 wt. % of C 3 A, 10.6 wt. % of C 4 AF and 5.9 wt. % of CS, and blast-furnace slag Portland cement (BFSPC) containing 30 wt. % of blast-furnace slag. Mortars with the above cements and siliceous sand with the weight ratio of 1 : 3 and water to cement ratio of 0.5 were manufactured and 40x40x160-mm prisms were stored at 20 °C for 90 days under 100% R.H. - wet air conditions. The physical-mechanical properties (strengths, dynamic modulus of elasticity...

Research paper thumbnail of Phase Compositions and Strengths of One-Year-Old Ternary Cement Composites

Research paper thumbnail of Efecto de la zeolita y de la mezcla zeolita-polvo de hierro en la durabilidad de la suspensión de cemento en agua con dióxido de carbono

La suspension de cemento-bentonita se utiliza con frecuencia para la construccion de muros pantal... more La suspension de cemento-bentonita se utiliza con frecuencia para la construccion de muros pantalla. Su mayor desventaja se halla en la resistencia relativamente baja a los medios liquidos agresivos. La suspension de cemento-bentonita endurecida presenta una importante perdida de peso y de resistencia a compresion conservada en agua saturada con 50 mg de CO2 por litro de solucion. Las probetas se estudian despues de 180 dias de exposicion. Por el contrario, las perdidas de peso y de resistencia a compresion son menores en la suspension de cementozeolita endurecida. Las probetas conservan una estructura rigida incluso despues de 365 dias de ataque con agua de CO2 (carbonica). La resistencia de la suspension de cemento-zeolita se incrementa aun mas con la adicion de polvo de hierro finamente molido. La adicion de zeolita contribuye a la reduccion de la formacion de Ca(OH)2 debido a la reaccion puzolanica de la zeolita, la cual consume el CaO libre y desarrolla una microestructura con ...

Research paper thumbnail of Influence of Portland cement addition to sulphoaluminate - belite cement on hydration and mechanical properties of hardened mortars

Ordinary Portland cement (PC), calcium sulphoaluminate - belite (SAB) cement and a 85 wt. % SAB c... more Ordinary Portland cement (PC), calcium sulphoaluminate - belite (SAB) cement and a 85 wt. % SAB cement/15 wt. % PC blend were used for mortar manufacture (cement to sand weight ratio 1 : 3, w/c ratio 0. 5) of 40×40×160 mm specimens kept in wet air cure (20°C, 100% R.H, for 90 days), and used for the tests. The results reveal the influence of cement type on mortar properties. The mortars, made from tested SAB cement have the worst mechanical properties. The replacement of 15 wt. % of SAB cement by PC contributes to the increase in dynamic modulus of elasticity (DME), flexural strength of the mortar by 15% and compressive strength almost by 40 % compared to the SAB cement mortar. Such mortar behaves mechanically similar to PC mortar. Differences in mechanical properties of mortars are caused by differences in chemical composition of cements (in SAB/PC mortar content of CaO is increased by 6.4 %, contents of Al 2 O 3 and Fe 2 O 3 are decreased by 8.2 % and 7.0%, respectively compared t...

Research paper thumbnail of Prospects of novel macro-defect-free cements for the new millennium

High strength cement-based materials developed recently are being used to explore new application... more High strength cement-based materials developed recently are being used to explore new applications which have not been possible with traditional cement and concrete technology. High flexural strength has not been a property typical of conventional cements, and thus there is no established position for cement technology in many modern industries. The relatively high cost of these materials has limited their uses in civil and architectural applications, which are very common for cements. Searching for new applications in areas currently dominated by metals, plastics and ceramics is a challenging task for cement scientists and engineers. Macrodefect-free (MDF) cement is a polymercement composite at the micrometer and nanometer levels. In these materials the polymer and cement react synergistically to create a unique microstructure with distinct characteristics. MDF cements were first reported [1,2] by the research group of Birchall at Imperial Chemical Industries plc (ICI, United Kingd...

Research paper thumbnail of 20th CTAS Annual Workshop and Exhibition : CTAS 2010 ()

Journal of Thermal Analysis and Calorimetry, 2011

Research paper thumbnail of Special Chapter on current topics at the Canadian Thermal Analysis Society (CTAS)

Journal of Thermal Analysis and Calorimetry, 2014

Research paper thumbnail of Macro-Defect-Free (MDF) Cements with High Moisture Resistance: Chemical, Thermal, SEM and Magnetometric Study

Solid State Phenomena, 2003

Research paper thumbnail of Influence of the material structure on the thermal conductivity of the clothing textiles

Journal of Thermal Analysis and Calorimetry, 2014

Comfort is seen as a comprehensive concept involving the transport of heat, moisture and air in t... more Comfort is seen as a comprehensive concept involving the transport of heat, moisture and air in the fabric of interactions and the human body on the basis of used material, design clothing and other parameters. These transports are slowed down or accelerated. One of the impulses for the detection of comfort is to know the impact of heat transfer, moisture through clothing that is intended to be precisely the objective of activity. Textiles intended for clothing would be reported in some places about the local compression behaviour, resistance to failure and increased transport sweat and moisture. Such clothing should allow ventilation to the outside and dry as quickly as possible, so after some activity remained, thermal resistance prevents the body hypothermia. Textiles are now designed not only to achieve certain properties, but also with respect to such security—sensors, the monitor’s vital functions of the body of the wearer.

Research paper thumbnail of Macrodefect-Free Cements: Chemistry and Impact of the Environment

Key Engineering Materials, 2002

Research paper thumbnail of Degree of hydration in cement paste and C3A-sodium carbonate-water systems

Journal of Thermal Analysis and Calorimetry, 2007

ABSTRACT This research provides a fundamental understanding of the early stage hydration of Portl... more ABSTRACT This research provides a fundamental understanding of the early stage hydration of Portland cement paste, tricalcium aluminate (C3A) paste at water to cement ratio of 0.5 and C3A suspension at water to cement ratio of 5.0 modified by 2 or 4 mass% of sodium carbonate. A high conversion of unreacted clinker minerals to gel-like hydration products in the cement-Na2CO3 pastes takes place rapidly between 1st to 24th h. Contrary the Ca(OH)2 formation within the same time interval is retarded in the excess of CO 32− ions due to intensive rise and growth of CaCO3 crystals in hydrated cement. Later, the conversion of clinker minerals to the hydrate phase is reduced and higher contents of calcite and vaterite relative to that of Ca(OH)2 in comparison with those found in the Portland cement paste are observed. As a consequence a decrease in strength and an increase in porosity between hardened Portland cement paste without sodium carbonate and those modified by Na2CO3 are observed. C3A hydrates very quickly with sodium carbonate between 1st and 24th h forming hydration products rich in bound water and characterized also by complex salts of (x)C3A·(y)CO2·(zH2O type, whereas C3A-H2O system offers C3AH6 as the main hydration product. Higher content of the formed calcium aluminate hydrates in C3A-Na2CO3-H2O system also contributes to early strength increase of Portland cement paste.

Research paper thumbnail of Special Chapter on Current Topics of CTAS2012

Journal of Thermal Analysis and Calorimetry, 2013

Research paper thumbnail of Thermal properties of textile fabrics

Journal of Thermal Analysis and Calorimetry, 2013

ABSTRACT Objective evaluation techniques were used in this study of thermal properties of textile... more ABSTRACT Objective evaluation techniques were used in this study of thermal properties of textile fabric. The Alambeta, P tester, and Togmeter measure the passages of air which were used for evaluation of the physiological properties. Fibrous materials were prepared in the form of textile knitting fabric COOLMAX. It is clear from the measurement that there are considerable differences in the results of measurement with described methods. Device Alambeta is convenient for the measurement and evaluation of various thermal properties. Finally, it can be concluded that this field of measurements is developing and will be the subject of further research of other methods, more suitable for measurement of the various characteristics.

Research paper thumbnail of 17 th Annual Meeting of the Canadian Thermal Analysis Society (CTAS) in conjunction with The 53 rd International Conference on Analytical Sciences and Spectroscopy (ICASS 2007)

Journal of Thermal Analysis and Calorimetry - J THERM ANAL CALORIM, 2008