scholarly journals The Effect of Gel-Type Contributions in Lime-Sand Bricks, Alkali-Activated Slags and CEMI/CEMIII Pastes: Implications for Next Generation Concretes

Gels ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 9
Author(s):  
Claus Henning Rüscher ◽  
Ludger Lohaus ◽  
Fongjan Jirasit ◽  
Hervé Kouamo Tchakouté
Keyword(s):  
Mechanical Strength ◽  
Silicate Solution ◽  
Cement Clinker ◽  
Atmospheric Conditions ◽  
Next Generation ◽  
X Ray Diffraction ◽  
Precursor State ◽  
X Ray ◽  
Alkali Silicate ◽  
Ray Patterns

Lime-sand bricks of different ages were investigated using IR-spectroscopy, thermogravimetry, and X-ray diffraction/scattering. After subtraction of the dominant quartz contribution (80%), the IR spectra show the absorption peaks of the hydrothermally formed binder phases. The spectra also show the alteration of the binder during ageing under atmospheric conditions by the influence of CO2 forming carbonate and a condensed SiO2-gel (secondary gel). The alteration could also be proven in X-ray pattern, obtaining a separation between crystalline CSH and amorphous contributions in the freshly produced lime-sand brick, too. Here, the formation of CSHamorph could be understood as a precursor state (primary gel) to the crystallization of CSH phases. X-ray patterns of aged bodies of alkali-silicate solution activated slags (AAS), CEM-I/CEM-III pastes, and CEM-I concrete indicate that in all cases a similar amorphous CSH-type phase (CSHamorph) was formed, which is responsible for the hardening properties as the glue. The main X-ray peak of CSHamorph obtained using CuKα-radiation with a usual diffractometer is observed between 24° and 35° 2 Theta with maximum at about 29° 2 Theta, whereas it appears much more broadly distributed between 15° and 35° 2 Theta with maximum between 26° and 28° 2 Theta for a geopolymer body prepared using the reaction of alkali-silicate solution and metakaolin (AAMK). This is due to the network formed by siloxo and sialate units in the case of AAMK, given that any crystallization can be ruled out. The origin of increasing mechanical strength during the ageing of AAS mortars must be due to further crosslinking of the preformed siloxo chains. Thermal treatment up to 800 °C leads to a complete loss of any mechanical strength of the CEM pastes due to the destruction of crystalline CSH-phases, whereas geopolymer bodies maintain their strength. Implications for next generation concrete include that cement clinker could be completely replaced by using a using alkali silcate solution technology for gel formation.

scholarly journals X-RAY DIFFRACTION STUDIES ON AMYLOID FILAMENTS

1968 ◽  
Vol 16 (11) ◽  
pp. 673-677 ◽  
Author(s):  
E. D. EANES ◽  
G. G. GLENNER
Keyword(s):  
Polypeptide Chain ◽  
X Ray Diffraction ◽  
X Ray ◽  
Filament Axis ◽  
Adjacent Chain ◽  
Diffuse Halo ◽  
Sheet Structure ◽  
Regular Manner ◽  
Ray Patterns ◽  
Pleated Sheet

The filamentous protein component of amyloid-laden tissue was studied by x-ray diffraction procedures. The principal features of the x-ray pattern from nonoriented amyloid material consist of a sharp, intense ring at 4.75 Å overlaying a diffuse halo at 4.3 Å, and a broad and less intense ring at 9.8 Å. When oriented, the material gives a "cross-β" x-ray pattern. The x-ray findings are interpreted in terms of a "pleated sheet" structure formed by the amyloid polypeptide chain folding in a regular manner on itself such that adjacent chain segments are laterally arranged in an antiparallel manner. The x-ray patterns from oriented amyloid suggest further that the axes of the chain segments run transverse to the filament axis.

scholarly journals Towards the Application of Supramolecular Self-Associating Amphiphiles as Next-Generation Delivery Vehicles

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4126
Author(s):  
Lisa J. White ◽  
Jessica E. Boles ◽  
Kira L. F. Hilton ◽  
Rebecca J. Ellaby ◽  
Jennifer R. Hiscock
Keyword(s):  
Gas Phase ◽  
High Resolution Mass Spectrometry ◽  
Next Generation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Guest Species ◽  
Solvent Environment ◽  
Delivery Vehicles ◽  
Self Association ◽  
Aqueous Conditions

Herein, we present a series of supramolecular self-associating amphiphilic (SSA) salts and establish the potential for these molecular constructs to act as next-generation solution-state molecular delivery vehicles. We characterise the self-association of these SSAs, both alone and when co-formulated with a variety of drug(like) competitive guest species. Single crystal X-ray diffraction studies enable the observation of hydrogen-bonded self-association events in the solid state, whilst high resolution mass spectrometry confirms the presence of anionic SSA dimers in the gas-phase. These same anionic SSA dimeric species are also identified within a competitive organic solvent environment (DMSO-d6/0.5% H2O). However, extended self-associated aggregates are observed to form under aqueous conditions (H2O/5.0% EtOH) in both the absence and presence of these competitive guest species. Finally, through the completion of these studies, we present a framework to support others in the characterisation of such systems.

Effects of CaF2 on the Formation Kinetics of Portland Cement Clinker

2011 ◽  
Vol 306-307 ◽  
pp. 966-969
Author(s):  
Chun Fang Wang ◽  
Zong Hui Zhou ◽  
Cai Xia Liu ◽  
Xin Cheng
Keyword(s):  
Portland Cement ◽  
Formation Rate ◽  
Reaction Rate Constant ◽  
Cement Clinker ◽  
X Ray Diffraction ◽  
Free Lime ◽  
X Ray ◽  
Formation Kinetics ◽  
Portland Cement Clinker ◽  
Kinetics Of

Through testing the amount of the free lime and the Loss ignition, the clinker formation rate, the reaction-rate constant (K) and the activation energy (Ea) were calculated according to the Gentling equation and Arrhenius equation. The effects of CaF2on the formation kinetics of Portland cement clinker were investigated by analyzing theKandEa. X-ray diffraction (XRD) and scanning electron Microscope (SEM) were used to characterize the phase composition and the morphology of the resulting samples. The results show that the silicate minerals formation is promoted when a proper amount of CaF2is doped into the raw meal. TheKincreased from 0.7450 ×10-5s-1to 7.1588 ×10-5s-1and theEadecreased from 386 kJ/mol to 122 kJ/mol when the amount of CaF2increased from 0.0% to 2.0% in mass. However, the results were reversed at the amount of CaF2exceeding 2%.

Effect of MgO on the Composition, Structure and Properties of Alite-Calcium Strontium Sulphoaluminate Cement

2010 ◽  
Vol 168-170 ◽  
pp. 472-477
Author(s):  
Chao Nan Yin ◽  
Ling Chao Lu ◽  
Shou De Wang ◽  
Ya Ming Chen
Keyword(s):  
Mass Fraction ◽  
Cement Clinker ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
Cement Production ◽  
X Ray ◽  
Sulphoaluminate Cement ◽  
Suitable Amount ◽  
Early Strength ◽  
Composition Structure

The influence of MgO on the composition, structure and properties of alite-calcium strontium sulphoaluminate cement were investigated by means of X-ray diffraction, SEM–EDS and light analysis. The results show that when the mass fraction of MgO is 1~5%, the early strength of cement can be enhanced significantly. The optimal content of MgO in the cement clinker is 2% and the compressive strengths of the cement at 3, 28 d are 64.3, 103.6 MPa respectively. A suitable amount of MgO can promote the formation of C1.5Sr2.5A3 , while the formation of C1.5Sr2.5A3 can be hindered if the content of MgO is excessive. The existence of MgO can improve the formation of C3S, increasing the mechanical property of the cement. Compared with the Portland cement, alite-calcium strontium sulphoaluminate cement has a higher capacity to dissolve MgO, which indicates that low-quality high-magnesium limestone can be efficiently used in the cement production.

Masquerade: removing non-sample scattering from integrated reflection intensities

2012 ◽  
Vol 45 (2) ◽  
pp. 292-298 ◽  
Author(s):  
J. A. Coome ◽  
A. E. Goeta ◽  
J. A. K. Howard ◽  
M. R. Probert
Keyword(s):  
Data Collection ◽  
Diffraction Data ◽  
Low Temperatures ◽  
Test Case ◽  
X Rays ◽  
Atmospheric Conditions ◽  
X Ray Diffraction ◽  
New Approach ◽  
X Ray ◽  
Internal Agreement

X-ray diffraction experiments at very low temperatures require samples to be isolated from atmospheric conditions and held under vacuum. These conditions are usually maintainedviathe use of beryllium chambers, which also scatter X-rays, causing unwanted contamination of the sample's diffraction pattern. The removal of this contamination requires novel data-collection and processing procedures to be employed. Herein a new approach is described, which utilizes the differences in origin of scattering vectors from the sample and the beryllium to eliminate non-sample scattering. The programMasqueradehas been written to remove contaminated regions of the diffraction data from the processing programs. Coupled with experiments at different detector distances, it allows for the acquisition of decontaminated data. Studies of several single crystals have shown that this approach increases data quality, highlighted by the improvement in internal agreement factor with the test case of cytidine presented herein.

scholarly journals The relationship between microstructure and mechanical properties of directly bonded copper-alumina ceramics joints

2014 ◽  
Vol 62 (1) ◽  
pp. 23-32 ◽  
Author(s):  
K. Pietrzak ◽  
W. Olesinska ◽  
D. Kalinski ◽  
A. Strojny-Nedza
Keyword(s):  
Mechanical Strength ◽  
Transition Layer ◽  
Diffraction Method ◽  
Alumina Ceramics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Three Point Bending ◽  
Microscopy Method ◽  
Materials Used ◽  
The Individual

Abstract The effect of phase transformations induced in the surface layer of alumina ceramics during its direct joining with copper activated with oxygen or titanium on the mechanical strength of the ceramic/copper joints was examined. The materials used in the experiments were an alumina single crystal, alumina ceramics (97.5 wt% Al2O3), the cermet mixtures: Cu-Cu2O with 10-50 wt% of Cu2O, copper with 5 wt% of Ti, and copper with 5 wt% of Ti and 10 wt% of Ag. The microstructure of the transition layer was examined by the X-ray diffraction method (XRD), scanning electron microscopy method (SEM) and energy dispersive x-ray spectroscopy (EDX). The mechanical strength of the joints was measured using the three-point bending method. The amount of oxygen optimal for the joining process was determined. It has been demonstrated that the cohesion of the joints depends not only on the formation of the individual phases but also, or even primarily, on the microstructure of the transition layer formed between them.

scholarly journals Anomalous reflexions in X-ray patterns

1941 ◽  
Vol 179 (976) ◽  
pp. 1-7 ◽  
Keyword(s):  
Simple Theory ◽  
Monochromatic Radiation ◽  
X Ray Diffraction ◽  
Satisfactory Explanation ◽  
Characteristic Radiation ◽  
X Ray ◽  
Diffraction Patterns ◽  
Ray Patterns

The presence on X-ray diffraction patterns of anomalous reflexions, that is to say, reflexions which cannot be accounted for by the simple theory of diffraction, is almost a commonplace. Many of these effects are no doubt to be ascribed to imperfections in the specimen, strains, etc., but even after these have been taken into account there remain streaks and spots for which there is no satisfactory explanation. The observation of effects of the type considered here is by no means novel; Friedrich (1913) recorded them as radial streaks running through the Laue spots in a photograph of KCl. The extra spots are generally very weak compared with the normal Laue reflexions and indeed may not be observed at all unless the photographs are somewhat over-exposed. They are most easily observed on Laue photographs taken with a tube emitting a characteristic radiation such as the K radiation of Cu or Ag, and their study will be greatly facilitated by the use of powerful sources of monochromatic radiation.

scholarly journals X-ray diffraction and SEM/EDX studies on technological evolution of the oxide-fluoride ceramic flux for submerged arc-surfacing

2012 ◽  
Vol 48 (1) ◽  
pp. 101-113 ◽  
Author(s):  
V.E. Sokolsky ◽  
A.S. Roik ◽  
A.V. Davidenko ◽  
V.P. Kazimirov ◽  
V.V. Lisnyak ◽  
...  
Keyword(s):  
Thermal Evolution ◽  
Silicate Solution ◽  
Component Composition ◽  
X Rays ◽  
X Ray Diffraction ◽  
Intensity Pattern ◽  
X Ray ◽  
Ceramic Flux ◽  
Main Component ◽  
Submerged Arc

The ceramic flux for submerged arc-surfacing with main component composition MgO (10.0 wt. %)-Al2O3 (25.0 wt. %)-SiO2 (40.0 wt. %)-CaF2 (25.0 wt. %) was prepared in a disk dryer-granulator using a sodium/potassium silicate solution as a binder. X-ray powder diffraction (XRPD) collected at r.t. identified ?- phase of quartz, Al2O3, MgO and CaF2 of the initial components in the samples taken after granulation and subsequent annealing at 600 ?C. In contrast to the low temperature annealing, anorthite (CaAl2Si2O8) is the main phase in the composition of the samples remelted at 1500 ?C and quenched subsequently. Chemical analysis performed by means of scanning electron microscopy with energy-dispersive X-ray spectroscopy analysis (SEM/EDX) detects that the grains of the remelted samples possess the same Ca : Al : Si elemental ratio as anorthite. High temperature X-ray diffraction (HTXRD) was used to examine structural transformation in the solid at 600 ?C < T < 1200 ?C and stages of thermal evolution of ceramic flux were determined. The ceramic flux melts completely at the temperature above 1350 ?C. The intensity pattern of the flux melt was obtained by X-ray diffraction of scattered X-rays at 1450 ?C. After calculating the structure factor (SF), the radial distribution function (RDF) was evaluated and used to calculate the structural basicity of the flux melt.

scholarly journals SÍNTESIS DE YAIO3 (YAP) POLICRISTALINO POR EL MÉTODO DE COMBUSTIÓN EN SOLUCIÓN

2018 ◽  
Vol 27 (1) ◽  
pp. 61
Author(s):  
A. Lazo ◽  
C. Paucarchuco ◽  
H. Loro
Keyword(s):  
Combustion Process ◽  
Orthorhombic Phase ◽  
Combustion Method ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
X Ray ◽  
Structure And Morphology ◽  
Palabras Clave ◽  
Diffraction Peaks ◽  
Ray Patterns

Se presenta el método de combustión en solución y su aplicación para la síntesis de YAlO3 (YAP), fueron usados como combustibles para la reacción de combustión y síntesis la urea y glicina, del YAP. Usando las técnicas de difracción de rayos X (XRD) por el método del polvo y microscopia electrónica de barrido (MEB) fueron analizadas la parte estructural y morfológica de las muestras obtenidas. Los difractogramas de Rayos X muestran una excelente correspondencia con lo reportado en la literatura para este material. Se suministran también los resultados de las muestras de material YAlxCrx‐1O3, dopado con Cr3+ con x = 0.001, 0.01, que exhiben picos de difracción dominantes debidos a la fase ortorrómbica de YAlO3 Palabras clave.- YAP, YAlO3, Combustion method. ABSTRACT The solution‐combustion process is presented, as well as its application to the synthesis of YAlO3 (YAP). Urea and glycine were used as fuel for the combustion reaction and synthesis of the YAP. The structure and morphology of the obtained sample were analyzed using the X‐ray diffraction (XRD) powder method and scanning electron microscopy (SEM). The X‐ray patterns showed an excellent agreement with data reported in the literature for this material. Results are also given for samples of YAlxCrx‐1O3 doped with Cr3+, with x = 0.001, 0.01, which showed dominant diffraction peaks due to the orthorhombic phase of YAlO3. Keywords.- YAP, YAlO3, combustion method.

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