scholarly journals The Effect of Fibrous Reinforcement on the Polycondensation Degree of Slag-Based Alkali Activated Composites

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2664
Author(s):  
Isabella Lancellotti ◽  
Federica Piccolo ◽  
Hoang Nguyen ◽  
Mohammad Mastali ◽  
Mohammad Alzeer ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Cellulose Fiber ◽  
Point Of View ◽  
Alkaline Media ◽  
Low Carbon ◽  
Integrity Test ◽  
Chemical Measurements ◽  
The Matrix ◽  
Alkaline Conditions ◽  
Alkali Activated

Alternative cementitious binders, based on industrial side streams, characterized by a low carbon footprint, are profitably proposed to partially replace Portland cement. Among these alternatives, alkali-activated materials have attracted attention as a promising cementitious binder. In this paper, the chemical stability of the matrix, in fiber-reinforced slag-based alkali-activated composites, was studied, in order to assess any possible effect of the presence of the reinforcement on the chemistry of polycondensation. For this purpose, organic fiber, cellulose, and an inorganic fiber, basalt, were chosen, showing a different behavior in the alkaline media that was used to activate the slag fine powders. The novelty of the paper is the study of consolidation by means of chemical measurements, more than from the mechanical point of view. The evaluation of the chemical behavior of the starting slag in NaOH, indeed, was preparatory to the understanding of the consolidation degree in the alkali-activated composites. The reactivity of alkali-activated composites was studied in water (integrity test, normed leaching test, pH and ionic conductivity), and acids (leaching in acetic acid and HCl attack). The presence of fibers does not favor nor hinder the geopolymerization process, even if an increase in the ionic conductivity in samples containing fibers leads to the hypothesis that samples with fibers are less consolidated, or that fiber dissolution contributes to the conductivity values. The amorphous fraction was enriched in silicon after HCl attack, but the structure was not completely dissolved, and the presence of an amorphous phase is confirmed (C–S–H gel). Basalt fibers partly dissolved in the alkaline environment, leading to the formation of a C–N–A–S–H gel surrounding the fibers. In contrast, cellulose fiber remained stable in both acidic and alkaline conditions.

scholarly journals Utilization of Blast Furnace Slag for Immobilization of Copper Ions from Solution

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Martin MUCHA ◽  
Lenka BLÁHOVÁ ◽  
Karolína PEŠOVÁ ◽  
Tomáš JUŘICA ◽  
Dimitrij KOLNIČENKO
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Structural Changes ◽  
Copper Ions ◽  
Alkali Activated Slag ◽  
The Matrix ◽  
Alkaline Conditions ◽  
Activated Slag ◽  
Furnace Slag ◽  
Alkali Activated

Disposal of wastes containing metal ions such as Cu(II) ions is serious problem nowadays. Various materials are utilized for thepurpose of immobilization of Cu(II) ions. Attractive type of material is represented by slags – waste from the metallurgical industry.Raw and alkali-activated blast furnace slag were studied for the purpose of immobilization of Cu(II) ions from the aqueoussolution and for disposal of Cu(II) containing wastes. Slags were saturated by Cu(II) ions. Amount of Cu(II) deposited on the rawslag was 6.35 ± 0.12 mg/g and amount deposited on the alkali-activated slag was 151.37 ± 0.95 mg/g. The saturated materialswere thermally treated at 100, 500, and 1000°C. The thermal treatment leads to the slight structural changes in the case of rawslag and to the significant structural changes in the case of alkali-activated slag. Cu(II) ions probably incorporate to the matrix ofmaterials. The materials based on alkali-activated slag exhibit higher stability to the leaching of Cu(II) ions compared to raw slagbased materials when only 0.13% of the total immobilized amount of Cu(II) ions was released to the solutions during the leachingexperiment in the case of alkali activated slag compared to 12% in the case of raw slag. The higher temperature of treatment leadsto more stable material in the case of both initial slags. The studied materials are less stable under the acidic conditions in comparisonwith the neutral and alkaline conditions. Alkali-activated blast furnace slag could be promising material for the Cu(II) ionsimmobilization and for the safe disposal of Cu(II) containing wastes.

scholarly journals Mine Clay Washing Residues as a Source for Alkali-Activated Binders

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 83
Author(s):  
Caterina Sgarlata ◽  
Alessandra Formia ◽  
Cristina Siligardi ◽  
Francesco Ferrari ◽  
Cristina Leonelli
Keyword(s):  
Ionic Conductivity ◽  
Chemical Stability ◽  
High Performance ◽  
Industrial Process ◽  
Strong Impact ◽  
Integrity Test ◽  
Homogeneous Microstructure ◽  
Calcined Clay ◽  
Alkali Activated Binders ◽  
Alkali Activated

The aim of this paper is to promote the use of mine clay washing residues for the preparation of alkali activated materials (AAMs). In particular, the influence of the calcination temperature of the clayey by-product on the geopolymerization process was investigated in terms of chemical stability and durability in water. The halloysitic clay, a mining by-product, has been used after calcination and mixed with an alkaline solution to form alkali activated binders. Attention was focused on the influence of the clay’s calcination treatment (450–500–600 °C) on the geopolymers’ microstructure of samples, remaining in the lower limit indicated by the literature for kaolinite or illite calcination. The mixtures of clay and alkali activators (NaOH 8M and Na-silicate) were cured at room temperature for 28 days. The influence of solid to liquid ratio in the mix formulation was also tested in terms of chemical stability measuring the pH and the ionic conductivity of the eluate after 24-h immersion time in water. The results reported values of ionic conductivity higher for samples made with untreated clay or with low temperature of calcination (≥756 mS/m) compared with values of samples made with calcined clay (292 mS/m). This result suggests that without a proper calcination of the as-received clay it was not possible to obtain 25 °C-consolidated AAMs with good chemical stability and dense microstructure. The measures of integrity test, pH, and ionic conductivity in water confirmed that the best sample is made with calcined clay at 600 °C, being similar (53% higher ionic conductivity of the eluate) or equal (integrity test and pH) to values recorded for the metakaolin-based geopolymer considered the reference material. These results were reflected in term of reticulation and morphology of samples through the analysis with scanning electron microscope (SEM) and X-ray diffraction (XRD), which show a dense and homogeneous microstructure predominantly amorphous with minor amounts of quartz, halloysite, and illite crystalline phases. Special attention was dedicated to this by-product to promote its use, given that kaolinite (and metakaolin), as primary mineral product, has a strong impact on the environment. The results obtained led us to consider this halloysite clay very interesting as an aluminosilicate precursor, and extensively deepening its properties and reactivity for the alkaline activation. In fact, the heart of this work is to study the possibility of reusing this by-product of an industrial process to obtain more sustainable high-performance binders.

The microstructure change of low-carbon electrical steels by residual aluminum

1989 ◽  
Vol 47 ◽  
pp. 286-287
Author(s):  
C.K. Hou ◽  
C.T. Hu ◽  
Sanboh Lee
Keyword(s):  
Annealing Treatment ◽  
Low Carbon ◽  
Electrical Steels ◽  
Vacuum Degassing ◽  
Spherical Inclusions ◽  
Residual Aluminum ◽  
Average Grain Size ◽  
The Matrix ◽  
Fine Size ◽  
To Come

The fully processed low-carbon electrical steels are generally fabricated through vacuum degassing to reduce the carbon level and to avoid the need for any further decarburization annealing treatment. This investigation was conducted on eighteen heats of such steels with aluminum content ranging from 0.001% to 0.011% which was believed to come from the addition of ferroalloys.The sizes of all the observed grains are less than 24 μm, and gradually decrease as the content of aluminum is increased from 0.001% to 0.007%. For steels with residual aluminum greater than 0. 007%, the average grain size becomes constant and is about 8.8 μm as shown in Fig. 1. When the aluminum is increased, the observed grains are changed from the uniformly coarse and equiaxial shape to the fine size in the region near surfaces and the elongated shape in the central region. SEM and EDAX analysis of large spherical inclusions in the matrix indicate that silicate is the majority compound when the aluminum propotion is less than 0.003%, then the content of aluminum in compound inclusion increases with that in steel.

Sorption of Cadmium and Lead by Chelating Ion Exchangers Ostsorb OXIN, Ostsorb DETA, and Ostsorb DTTA

1994 ◽  
Vol 59 (6) ◽  
pp. 1311-1318 ◽  
Author(s):  
Ladislav Svoboda ◽  
Petr Vořechovský
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Sodium Perchlorate ◽  
Exchange Capacity ◽  
Chloride Ions ◽  
Point Of View ◽  
Alkaline Media ◽  
Ion Exchangers ◽  
Acidic Media ◽  
Cadmium And Lead

The properties of cellulose chelating ion exchangers Ostsorb have been studied in the sorption of cadmium and lead from aqueous solutions. The Cd(II) and Pb(II) ions are trapped by the Ostsorb OXIN and Ostsorb DETA ion exchangers most effectively in neutral and alkaline media but at these conditions formation of stable hydrolytic products of both metals competes with the exchange equilibria. From this point of view, Ostsorb DTTA appears to be a more suitable sorbent since it traps the Pb(II) and Cd(II) ions in acidic media already. Chloride ions interfere with the sorption of the two metals by Ostsorb DTTA whereas the ionic strength adjusted by the addition of sodium perchlorate does not affect the exchange capacity of this ion exchanger.

scholarly journals Matrix integrals & finite holography

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Dionysios Anninos ◽  
Beatrix Mühlmann
Keyword(s):  
Critical Exponents ◽  
Continuum Theory ◽  
Point Of View ◽  
Leading Order ◽  
Minimal Models ◽  
Point Evaluation ◽  
Brst Cohomology ◽  
Matrix Integrals ◽  
The Matrix ◽  
The Continuum

Abstract We explore the conjectured duality between a class of large N matrix integrals, known as multicritical matrix integrals (MMI), and the series (2m − 1, 2) of non-unitary minimal models on a fluctuating background. We match the critical exponents of the leading order planar expansion of MMI, to those of the continuum theory on an S2 topology. From the MMI perspective this is done both through a multi-vertex diagrammatic expansion, thereby revealing novel combinatorial expressions, as well as through a systematic saddle point evaluation of the matrix integral as a function of its parameters. From the continuum point of view the corresponding critical exponents are obtained upon computing the partition function in the presence of a given conformal primary. Further to this, we elaborate on a Hilbert space of the continuum theory, and the putative finiteness thereof, on both an S2 and a T2 topology using BRST cohomology considerations. Matrix integrals support this finiteness.

Overall Planning of Shanghai New Trade Zone from an Ecological Economic Perspective

2017 ◽  
Vol 42 (3) ◽  
pp. 40-44
Author(s):  
Wence Yu ◽  
Hao Chen ◽  
LiQiang Yang
Keyword(s):  
Free Trade ◽  
Free Trade Area ◽  
Point Of View ◽  
Free Trade Zone ◽  
System Structure ◽  
Low Carbon ◽  
Economic Perspective ◽  
Free Trade Areas ◽  
Ecological Economic ◽  
Trade Area

Since the reform and opening up, the economy of China has rapidly developed. The system, structure, mode, and pattern of the foreign trade in China must be adjusted accordingly to adapt to new economic normality. In this study, the main types of free trade areas worldwide were analyzed, and the necessary conditions for their successful development were examined on the basis of an ecological economic perspective. The Shanghai free trade area is a typical representative of a new type of Trade Zone in China. It introduces the principles of sustainable development, people oriented, green, low-carbon and other eco free trade zones. The planning characteristics of Shanghai free trade zone were studied from the point of view of planning economy and land use. Taking Shanghai Yangshan land free trade zone as an example, the planning research was carried out in terms of functional zoning, environment, transportation and facilities. In summary, this study provided theoretical and technical references for the construction of free trade areas and for the formulation of significant policies.

Fibre-Matrix Interface Development during High Temperature Exposition of Long Fibre Reinforced SiOC Matrix

2013 ◽  
Vol 592-593 ◽  
pp. 401-404
Author(s):  
Zdeněk Chlup ◽  
Martin Černý ◽  
Adam Strachota ◽  
Martina Halasova ◽  
Ivo Dlouhý
Keyword(s):  
High Temperature ◽  
Crack Formation ◽  
Fracture Behaviour ◽  
Point Of View ◽  
Reinforced Composites ◽  
Matrix Interface ◽  
Significant Damage ◽  
The Matrix ◽  
Fibre Matrix ◽  
Fibre Reinforced Composites

The fracture behaviour of long fibre reinforced composites is predetermined mainly by properties of fibre-matrix interface. The matrix prepared by pyrolysis of polysiloxane resin possesses ability to resist high temperatures without significant damage under oxidising atmosphere. The application is therefore limited by fibres and possible changes in the fibre matrix interface. The study of development of interface during high temperature exposition is the main aim of this contribution. Application of various techniques as FIB, GIS, TEM, XRD allowed to monitor microstructural changes in the interface of selected places without additional damage caused by preparation. Additionally, it was possible to obtain information about damage, the crack formation, caused by the heat treatment from the fracture mechanics point of view.

scholarly journals Development of technology of industrial wastes treatment products disposal by ferritization in the matrix of alkali-activated cements

2018 ◽  
Vol 6 (3(44)) ◽  
pp. 31-35 ◽  
Author(s):  
Gennadii Kochetov ◽  
Dmitry Samchenko ◽  
Anton Kolodko ◽  
Oleksandr Kovalchuk ◽  
Anton Pasko
Keyword(s):  
Industrial Wastes ◽  
The Matrix ◽  
Alkali Activated

scholarly journals MYSTERY AS A META-GENRE IN THE DRAMA OF THE TWENTIETH CENTURY

2021 ◽  
pp. 18-26
Author(s):  
K. Oliinyk
Keyword(s):  
Twentieth Century ◽  
World Order ◽  
Semantic Content ◽  
Point Of View ◽  
Dramatic Works ◽  
Life And Death ◽  
The Matrix ◽  
General Feeling ◽  
The Aesthetic ◽  
Definition Of

The article examines the specificity of existence of the renewed mystery genre as a meta genre in the twentieth century. The main literary study views on the definition of ancient and medieval / Christian ritual mystery are analyzed. The beginning of the twentieth century was full of a general feeling of catastrophe and tragic hopelessness. In artistic terms, the consequence of this was the activation of Christian issues, motives, plots, religious genres (miracles, morality and mystery). The most universal from the point of view of the ideological message and content for the writers of the twentieth century. was the matrix of the medieval mystery, which retained the ritual basis in its primary structure. This made it possible for the multilevel organization of the action and the space for it. The genre of medieval mystery is being modified, it ceases to be a purely form of religious action and acquires the quality of a meta genre. There is a transition from the religious sphere to the secular one, and the aesthetic one is replacing the didactic load. Mystery begins to exist on the edge of genres as a synthetic formation, showing intentions to “help” other genres. A large number of dramatic works of the twentieth century. ("Forest Song" by Lesia Ukrainka, "Iconostasis of Ukraine" by Vіra Vovk) comes close to the mystery, using its archetypal components: the ideas of faith in the absolute beginning, governing the eternal rotation of life and death, world order and harmony, death and rebirth, transformations of the human soul, chosenness and initiation associated with trials, sacrifice, deepening into mysticism. Such works are a certain imitation with elements of mythological or religious subjects. So, the twentieth century, actualizes a certain involvement of the semantic content of dramas to the mysteries, bringing the mystery to the level of the meta genre.

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