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Online since: June 2018
Authors: Olesia Mikhailova, Pavel Rovnaník
The rheological properties and hydration process of slag-blended cement pastes in the presence of polycarboxylate superplasticizers with different structure were studied in [10].
Of the 4th International Conference on the Durability of Concrete Structures, West Lafayette, IN, USA, July (2014) 254–261
Repette, Effect of different activators type and dosages and relation with autogenous shrinkage of activated blast furnace slag cement, Proc. of the 11th International Congress on the Chemistry of Cement, Durban, South Africa (2003) 1878–1888
Qiao, Jannie S.J. van Deventer, The interrelationship between surface chemistry and rheology in alkali activated slag paste, Construction and Building Materials. 65 (2014) 583–591
Banfill, The rheology of fresh cement and concrete − a review, Proc. 11th International Cement Chemistry Congress, Durban, May 2003
Of the 4th International Conference on the Durability of Concrete Structures, West Lafayette, IN, USA, July (2014) 254–261
Repette, Effect of different activators type and dosages and relation with autogenous shrinkage of activated blast furnace slag cement, Proc. of the 11th International Congress on the Chemistry of Cement, Durban, South Africa (2003) 1878–1888
Qiao, Jannie S.J. van Deventer, The interrelationship between surface chemistry and rheology in alkali activated slag paste, Construction and Building Materials. 65 (2014) 583–591
Banfill, The rheology of fresh cement and concrete − a review, Proc. 11th International Cement Chemistry Congress, Durban, May 2003
Online since: June 2019
Authors: Dalibor Kocáb, Barbara Kucharczyková, Martin Alexa, Jan Kotrla
Experimental Determination of Early Shrinkage of Alkali-Activated Slag
Martin ALEXA1,a*, Dalibor KOCÁB1,b,
Barbara KUCHARCZYKOVÁ1,c and Jan KOTRLA2,d
1Brno University of Technology, Faculty of Civil Engineering, Veveří 331/95, 602 00 Brno, Czech Republic
2Brno University of Technology, Faculty of Chemistry, Purkyňova 464/118, 612 00 Brno, Czech Republic
amartin.alexa@vutbr.cz, bdalibor.kocab@vutbr.cz, cbarbara.kucharczykova@vutbr.cz, dxckotrla@fch.vut.cz
Keywords: Alkali-Activated Slag, Shrinkage, Volume Changes, Isopropyl Alcohol.
They harden due to inorganic polycondensation reactions during which the dissolved aluminate and silicate anions merge via oxygen atoms and form an amorphous or semi-crystalline phase (C-A-S-H gel), wherein its structure varies depending on the used raw materials [2,3].
The shrinkage process is associated with water, which is located between the hydrating grains, and shrinkage itself occurs when water molecules escape from the structure.
Davidovits, Geopolymer, green chemistry and sustainable development solutions: proceedings of the World Congress Geopolymer 2005, Saint-Quentin (France), Geopolymer Institute, 2005
Davidovits, Geopolymer: chemistry, 2nd ed., Saint-Quentin (France), Geopolymer Institute, 2008
They harden due to inorganic polycondensation reactions during which the dissolved aluminate and silicate anions merge via oxygen atoms and form an amorphous or semi-crystalline phase (C-A-S-H gel), wherein its structure varies depending on the used raw materials [2,3].
The shrinkage process is associated with water, which is located between the hydrating grains, and shrinkage itself occurs when water molecules escape from the structure.
Davidovits, Geopolymer, green chemistry and sustainable development solutions: proceedings of the World Congress Geopolymer 2005, Saint-Quentin (France), Geopolymer Institute, 2005
Davidovits, Geopolymer: chemistry, 2nd ed., Saint-Quentin (France), Geopolymer Institute, 2008
Online since: January 2013
Authors: Yang Yu, Zhen Ping Sun, Qi Li, Pei Qiang Yang
Introduction
Since nuclear magnetic resonance phenomena has been discovered by Bloch and Purcell in 1945, nuclear magnetic resonance (NMR) has been utilized in different fields, such as material structure, MRI, logging and so on [1].
Low-field NMR has been employed to characterize pore structure [3,4,5], to monitor cement hydration[6,7,8], and to image[9,10].
T2 distributions of F315 was bimodal and in this paper, we named peak on the left side ‘short component’ and peak on the right side ‘long component’.According to cement chemistry, tri-calcium aluminate (C3A), with a higher reactivity than other minerals, dissolved fast after cement being mixed with water and was positively charged because of adsorption of calcium ions; a silicon-rich layer emerged on tri-calcium silicate (C3S) and was negatively charged for a lower affinity to calcium ions than interstitial phase.
According to cement chemistry, hydration of cement could be divided into four stages, that is, initial stage, dormant stage, accelerated stage and steady stage.
Taylor: Cement chemistry (Thomas Telford Publishing, USA,1992)
Low-field NMR has been employed to characterize pore structure [3,4,5], to monitor cement hydration[6,7,8], and to image[9,10].
T2 distributions of F315 was bimodal and in this paper, we named peak on the left side ‘short component’ and peak on the right side ‘long component’.According to cement chemistry, tri-calcium aluminate (C3A), with a higher reactivity than other minerals, dissolved fast after cement being mixed with water and was positively charged because of adsorption of calcium ions; a silicon-rich layer emerged on tri-calcium silicate (C3S) and was negatively charged for a lower affinity to calcium ions than interstitial phase.
According to cement chemistry, hydration of cement could be divided into four stages, that is, initial stage, dormant stage, accelerated stage and steady stage.
Taylor: Cement chemistry (Thomas Telford Publishing, USA,1992)
Online since: March 2018
Authors: Aleksey A. Vedyagin, Elena Krivoshapkina, Pavel Krivoshapkin
Petersburg, 197101, Russian Federation
2Institute of Chemistry of Komi SC UB RAS, Syktyvkar, 167982, Russian Federation
3Boreskov Institute of Catalysis SB RAS, Novosibirsk, 630090, Russian Federation
4National Research Tomsk Polytechnic University, Tomsk, 634050, Russian Federation
avedyagin@catalysis.ru
Keywords: Alumina, Sol-gel synthesis, Nanofiber, Nanoparticle, Cu-Co-Ce-O catalyst.
On the other hand, fibers and fibrous materials are of wide interest in the field of applied chemistry and materials science.
Most probably, the higher activity of the catalyst supported on alumina nanofibers is connected with its optimal geometric form and porous structure.
The developed catalytic system is characterized by a relatively low cost, an optimal hierarchical pore structure, and appropriate catalytic activity.
The experiments were performed using the equipment of the Center for Shared Use of Scientific Equipment “Khimiya” of the Institute of Chemistry, Komi Science Center, Ural Branch of the Russian Academy of Sciences.
On the other hand, fibers and fibrous materials are of wide interest in the field of applied chemistry and materials science.
Most probably, the higher activity of the catalyst supported on alumina nanofibers is connected with its optimal geometric form and porous structure.
The developed catalytic system is characterized by a relatively low cost, an optimal hierarchical pore structure, and appropriate catalytic activity.
The experiments were performed using the equipment of the Center for Shared Use of Scientific Equipment “Khimiya” of the Institute of Chemistry, Komi Science Center, Ural Branch of the Russian Academy of Sciences.
Online since: August 2019
Authors: Luiza I. Kitieva, Zakhirat Sultigova, Timur A. Borukaev
Therefore, it can be assumed that ZB particles do not cause the formation of defective structures in the polymer matrix, but rather contribute to the formation of a less defective structure.
The effect of micro- and nanoparticles of zinc borate on the flammability of composite material based on polymethyl methacrylate, Advances in chemistry and chemical technology. 6 (165) (2015) 99-101
Polymer combustion and flame retardant mechanisms, Chemistry Aadvances. 53 (2) (1984) 326-330
Flame retardants of polymeric materials, Chemistry, Moscow, 1980, pp. 100-200
The effect of micro- and nanoparticles of zinc borate on the flammability of composite material based on polymethyl methacrylate, Advances in chemistry and chemical technology. 6 (165) (2015) 99-101
Polymer combustion and flame retardant mechanisms, Chemistry Aadvances. 53 (2) (1984) 326-330
Flame retardants of polymeric materials, Chemistry, Moscow, 1980, pp. 100-200
Online since: April 2021
Authors: Bing Jun Shen, Li Hong Jin, Ling Yu Li, Jian Tian, Xing Ye Wang
Although there are many phenomena in this field that cannot be explained by traditional physics, chemistry and nuclear physics theories, the theoretical significance that may bring breakthroughs and the application prospects of becoming a new type of clean energy continue to attract the attention of researchers[2-8].
Figure 1 was a schematic diagram of the experimental system structure.
Figure 2 showed a schematic diagram of the structure of the 9_reaction chamber.
Acknowledgements This work was financially supported by National Natural Science Foundation of China (21153003) This paper has been carefully guided by Wushou Zhang from the Institute of Chemistry Chinese Academy of Sciences on the testing, installation and use of testing software.
Chemistry.
Figure 1 was a schematic diagram of the experimental system structure.
Figure 2 showed a schematic diagram of the structure of the 9_reaction chamber.
Acknowledgements This work was financially supported by National Natural Science Foundation of China (21153003) This paper has been carefully guided by Wushou Zhang from the Institute of Chemistry Chinese Academy of Sciences on the testing, installation and use of testing software.
Chemistry.
Online since: September 2017
Authors: A.A. Kravchenko, D.I. Dyachenko, V.T. Fomichev
Cobalt serves also as a model system for the macroscopic magnetic response because the low to moderate crystal anisotropy allows the effects of size, shape, internal crystal structure, and surface anisotropy to be observed in a single system [2,3].
They have sufficiently high ionic conductivity, wide electrochemical window (which often in excess of 5 volts), great dissolving power and in addition RTILs correspond to principles of green chemistry.
Moreover, in terms of physical chemistry, ionic structure of RTILs allows to expect the exhibition of well stabilization properties.
Chemistry.
They have sufficiently high ionic conductivity, wide electrochemical window (which often in excess of 5 volts), great dissolving power and in addition RTILs correspond to principles of green chemistry.
Moreover, in terms of physical chemistry, ionic structure of RTILs allows to expect the exhibition of well stabilization properties.
Chemistry.
Online since: December 2014
Authors: Yu Guang Wang, Jin Long Zhuo, Xiao Qing Dai, Guo Dong Liu
Key Laboratory of Inorganic Chemistry in Universities of Shandong, Department of Chemistry and Chemical engineering, Jining University, Qufu 273155 ,China; 2.
The results shown that the sample synthesized at 650 oC is pure olivine structure LiFePO4 with a particle size of 1-2μm, and it exhibits an initial discharge specific capacitance of 158.3mAh/g under 0.2 C rate in the voltage of 2.5-4.2V, which remain well after 20 cycles.
The results show that material with a single olivine structure, rules of the sample morphology and particle uniformity.
Du: Chinese Journal Inorganic Chemistry, Vol.26 (2010) No.6, p. 1061.
The results shown that the sample synthesized at 650 oC is pure olivine structure LiFePO4 with a particle size of 1-2μm, and it exhibits an initial discharge specific capacitance of 158.3mAh/g under 0.2 C rate in the voltage of 2.5-4.2V, which remain well after 20 cycles.
The results show that material with a single olivine structure, rules of the sample morphology and particle uniformity.
Du: Chinese Journal Inorganic Chemistry, Vol.26 (2010) No.6, p. 1061.
Online since: January 2016
Authors: Azreena Mastor, Siti Hajar Kasim, Abdul Yazid Abdul Manaf, Siti Farhana Hisham, Kartini Noorsal, Norhidayah Abu, Siti Noorzidah Mohd Sabri, Syazana Abu Bakar, Ahmad Hazri Abdul Rashid
Besides, the versatility of using chitosan in the biomedical and biotechnological fields are enhanced by its immunostimulation, activation of macrophages, mucoadhesion, antimicrobial activity and well assessed chemistry properties.
This analysis observed the surface structure of break area on the samples after the tensile test.
The new covalent bonding occurred by cross-linking reaction has improved the interphase structure of chitosan matrix by forming more expansible network.
Martinelli, Preparation and characterization of chitosan/genipin/poly(N-vinyl-2-pyrrolidone) films for controlled release drugs, Materials Chemistry and Physics. 134 (2012) 317-324
Martinelli, Preparation and characterization of chitosan/genipin/poly(N-vinyl-2-pyrrolidone) films for controlled release drugs, Materials Chemistry and Physics. 134 (2012) 317-324
This analysis observed the surface structure of break area on the samples after the tensile test.
The new covalent bonding occurred by cross-linking reaction has improved the interphase structure of chitosan matrix by forming more expansible network.
Martinelli, Preparation and characterization of chitosan/genipin/poly(N-vinyl-2-pyrrolidone) films for controlled release drugs, Materials Chemistry and Physics. 134 (2012) 317-324
Martinelli, Preparation and characterization of chitosan/genipin/poly(N-vinyl-2-pyrrolidone) films for controlled release drugs, Materials Chemistry and Physics. 134 (2012) 317-324
Online since: June 2010
Authors: Xiao Hua Lu, Yi Jun Shi, Xin Feng, Huai Yuan Wang, Li Wen Mu
Friction and Wear Behaviors of Solid Lubricants/Polyimide Composites
in Liquid Mediums
Liwen Mu1a, Xin Feng
*1b, Yijun Shi1,2c, Huaiyuan Wang3d, Xiaohua Lu1e
1 State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing University of
Technology, Nanjing 210009, China
2 Department of Chemistry and Materials Science, Institute of Science, Nanjing Forestry University,
Nanjing 210037, China
3 College of Chemistry & Chemical Engineering, Daqing Petroleum Institute, Daqing, 163318,
China) *Corresponding and presenting authors.
The solid lubricants with a layered crystal structure shear easily to provide low friction and to prevent wear damage between the sliding surfaces.
Upon exposure to humid or oxidative environments, MoS2 may undergo irreversible structural-chemistry changes that in turn lead to loss of lubricity and the generation of some abrasive by-products [9].
The spherical structure [Fig. 5] that accumulated on the worn surface during sliding can act as nano-ball rolling effect on the frictional surface.
The solid lubricants with a layered crystal structure shear easily to provide low friction and to prevent wear damage between the sliding surfaces.
Upon exposure to humid or oxidative environments, MoS2 may undergo irreversible structural-chemistry changes that in turn lead to loss of lubricity and the generation of some abrasive by-products [9].
The spherical structure [Fig. 5] that accumulated on the worn surface during sliding can act as nano-ball rolling effect on the frictional surface.